How do i reset my blink password

Q: How do I get into my Blink account?

Open your Blink app and press I already have an account. You will then need to enter either your email or mobile number that is listed on your account and complete the method of authentication.

You can change your password in the “Account Details” section of “My Account”. Simply scroll down to Password Change section. You will then be asked to enter both your old and new passwords.

If you can’t remember your password, click “Forgot your password?” on the login screen. You will be asked to confirm your email address and click Reset password. After that, check your inbox for an email with instructions for resetting your password.

Blink is a self-service password reset tool and app that allows users to reset their own passwords without having to contact their IT Department or TMPros. Everything will be done within a dedicated app that is available for all iOS and Android devices. On top of allowing password self-resets, Blink will also proactively monitor your account and let you know when a lockout has occurred.

This user guide is designed to help you become acquainted with Blink and the steps leading to correct activation.

Blink is a feature that allows users to request a new password for their Windows account via SMS or Android/iOS App. It is fast, secure and involves no technician during the reset process.

/ {
    fragment@0 {
        target-path = "/";
        __overlay__ {

            test: test_node {
                string = "hello";
                status = "disabled";
                bytes = /bits/ 8 <0x67 0x89>;
                u16s = /bits/ 16 <0xabcd 0xef01>;
                u32s = /bits/ 32 <0xfedcba98 0x76543210>;
                u64s = /bits/ 64 < 0xaaaaa5a55a5a5555 0x0000111122223333>;
                bool1; // Defaults to true
                       // bool2 defaults to false
                mac = [01 23 45 67 89 ab];
                spi = <&spi0>;
            };
        };
    };

    fragment@1 {
        target-path = "/";
        __overlay__ {
            frag1;
        };
    };

    fragment@2 {
        target-path = "/";
        __dormant__ {
            frag2;
        };
    };

    __overrides__ {
        string =      <&test>,"string";
        enable =      <&test>,"status";
        byte_0 =      <&test>,"bytes.0";
        byte_1 =      <&test>,"bytes.1";
        u16_0 =       <&test>,"u16s;0";
        u16_1 =       <&test>,"u16s;2";
        u32_0 =       <&test>,"u32s:0";
        u32_1 =       <&test>,"u32s:4";
        u64_0 =       <&test>,"u64s#0";
        u64_1 =       <&test>,"u64s#8";
        bool1 =       <&test>,"bool1!";
        bool2 =       <&test>,"bool2?";
        entofr =      <&test>,"english",
                      <&test>,"french{hello=bonjour,goodbye='au revoir',weekend}";
        pi_mac =      <&test>,"mac[{1=b8273bfedcba,2=b8273b987654}";
        spibus =      <&test>,"spi:0[0=",<&spi0>,"1=",<&spi1>,"2=",<&spi2>;

        only1 =       <0>,"+1-2";
        only2 =       <0>,"-1+2";
        enable1 =     <0>,"=1";
        disable2 =    <0>,"!2";
    };
};

This is a guide to using YubiKey as a SmartCard for storing GPG encryption, signing and authentication keys, which can also be used for SSH. Many of the principles in this document are applicable to other smart card devices.

Keys stored on YubiKey are non-exportable (as opposed to file-based keys that are stored on disk) and are convenient for everyday use. Instead of having to remember and enter passphrases to unlock SSH/GPG keys, YubiKey needs only a physical touch after being unlocked with a PIN. All signing and encryption operations happen on the card, rather than in OS memory.

Tip drduh/Purse is a password manager which uses GPG and YubiKey to securely store and read credentials.

Security Note: If you followed this guide before Jan 2021, your GPG PIN and Admin PIN may be set to their default values (

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

58 and

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

59 respectively). This would allow an attacker to use your Yubikey or reset your PIN. Please see the Change PIN section for details on how to change your PINs.

If you have a comment or suggestion, please open an Issue on GitHub.

Purchase
Prepare environment
Required software
- Debian and Ubuntu
- Fedora
- Arch
- RHEL7
- NixOS
- OpenBSD
- macOS
- Windows
Entropy
- YubiKey
- OneRNG
Creating keys
- Temporary working directory
- Harden configuration
Master key
Sign with existing key
Sub-keys
- Signing
- Encryption
- Authentication
- Add extra identities
Verify
Export secret keys
Revocation certificate
Backup
Export public keys
Configure Smartcard
- Enable KDF
- Change PIN
- Set information
Transfer keys
- Signing
- Encryption
- Authentication
Verify card
Multiple YubiKeys
- Switching between two or more Yubikeys
Cleanup
Using keys
Rotating keys
- Setup environment
- Renewing sub-keys
- Rotating keys
Adding notations
SSH
- Create configuration
- Replace agents
- Copy public key
- (Optional) Save public key for identity file configuration
- Connect with public key authentication
- Import SSH keys
- Remote Machines (SSH Agent Forwarding)
  - Use ssh-agent
  - Use S.gpg-agent.ssh
  - Chained SSH Agent Forwarding
- GitHub
- OpenBSD
- Windows
  - WSL
    - Use ssh-agent or use S.weasel-pegant
    - Prerequisites
    - WSL configuration
    - Remote host configuration
- macOS
Remote Machines (GPG Agent Forwarding)
- Steps for older distributions
- Chained GPG Agent Forwarding
Using Multiple Keys
Require touch
Email
- Mailvelope on macOS
- Mutt
Reset
Recovery after reset
Notes
Troubleshooting
Alternatives
- Create keys with batch
Links

Purchase

All YubiKeys except the blue "security key" model and the "Bio Series - FIDO Edition" are compatible with this guide. NEO models are limited to 2048-bit RSA keys. Compare YubiKeys here. A list of the YubiKeys compatible with OpenPGP is available here. In May 2021, Yubico also released a press release and blog post about supporting resident ssh keys on their Yubikeys including blue "security key 5 NFC" with OpenSSH 8.2 or later, see here for details.

To verify a YubiKey is genuine, open a browser with U2F support to https://www.yubico.com/genuine/. Insert a Yubico device, and select Verify Device to begin the process. Touch the YubiKey when prompted, and if asked, allow it to see the make and model of the device. If you see Verification complete, the device is authentic.

This website verifies YubiKey device attestation certificates signed by a set of Yubico certificate authorities, and helps mitigate supply chain attacks.

You will also need several small storage devices (microSD cards work well) for storing encrypted backups of your keys.

Prepare environment

To create cryptographic keys, a secure environment that can be reasonably assured to be free of adversarial control is recommended. Here is a general ranking of environments most to least likely to be compromised:

Daily-use operating system
Virtual machine on daily-use host OS (using virt-manager, VirtualBox, or VMware)
Separate hardened Debian or OpenBSD installation which can be dual booted
Live image, such as Debian Live or Tails
Secure hardware/firmware (Coreboot, Intel ME removed)
Dedicated air-gapped system with no networking capabilities

This guide recommends using a bootable "live" Debian Linux image to provide such an environment, however, depending on your threat model, you may want to take fewer or more steps to secure it.

To use Debian Live, download the latest image:

$ curl -LfO https://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/SHA512SUMS

$ curl -LfO https://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/SHA512SUMS.sign

$ curl -LfO https://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/$(awk '/xfce.iso/ {print $2}' SHA512SUMS)

Verify the signature of the hashes file with GPG:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

If the public key cannot be received, try changing the DNS resolver and/or use a different keyserver:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Ensure the SHA512 hash of the live image matches the one in the signed file - if there following command produces output, it is correct:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

See Verifying authenticity of Debian CDs for more information.

Mount a storage device and copy the image to it:

Linux

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

OpenBSD

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

Shut down the computer and disconnect internal hard drives and all unnecessary peripheral devices. If being run within a VM, this part can be skipped as no such devices should be attached to the VM since the image will still be run as a "live image".

Required software

Boot the live image and configure networking.

Note If the screen locks, unlock with

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

60/

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

61.

Open the terminal and install required software packages.

Debian and Ubuntu

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Note Live Ubuntu images may require modification to

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

62 and may need additional packages:

$ sudo apt -y install libssl-dev swig libpcsclite-dev

Optional Install the

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

63 utility, which will allow you to enable touch policies (requires admin PIN):

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

Fedora

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

Arch

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

RHEL7

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

NixOS

Generate an air-gapped NixOS LiveCD image with the given config:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Build the installer and copy it to a USB drive.

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

With this image, you won't need to manually create a temporary working directory or harden the configuration, as it was done when creating the image.

OpenBSD

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

macOS

Download and install Homebrew and the following packages:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Note An additional Python package dependency may need to be installed to use

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

63 -

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Windows

Download and install Gpg4Win and PuTTY.

You may also need more recent versions of yubikey-personalization and yubico-c.

Entropy

Generating cryptographic keys requires high-quality randomness, measured as entropy.

Most operating systems use software-based pseudorandom number generators or CPU-based hardware random number generators (HRNG).

Optionally, you can use a separate hardware device like OneRNG to increase the speed of entropy generation and possibly also the quality.

YubiKey

YubiKey firmware version 5.2.3 introduced "Enhancements to OpenPGP 3.4 Support" - which can optionally gather additional entropy from YubiKey via the SmartCard interface.

To seed the kernel's PRNG with additional 512 bytes retrieved from the YubiKey:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

OneRNG

Install rng-tools software:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Plug in the device and restart rng-tools:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Creating keys

Temporary working directory

Create a temporary directory which will be cleared on reboot and set it as the GnuPG directory:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Otherwise, to preserve the working environment, set the GnuPG directory to your home folder:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Harden configuration

Create a hardened configuration in the temporary working directory with the following options:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Important Disable networking for the remainder of the setup.

Master key

The first key to generate is the master key. It will be used for certification only: to issue sub-keys that are used for encryption, signing and authentication.

Important The master key should be kept offline at all times and only accessed to revoke or issue new sub-keys. Keys can also be generated on the YubiKey itself to ensure no other copies exist.

You'll be prompted to enter and verify a passphrase - keep it handy as you'll need it multiple times later.

Generate a strong passphrase which could be written down in a secure place or memorized:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Use upper case letters for improved readability if passwords are written down by hand:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Important Save this credential in a permanent, secure place as it will be needed to issue new sub-keys after expiration, and to provision additional YubiKeys, as well as to your Debian Live environment clipboard, as you'll need it several times throughout to generate keys.

Tip On Linux or OpenBSD, select the password using the mouse or by double-clicking on it to copy to clipboard. Paste using the middle mouse button or

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

66-

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

67.

Generate a new key with GPG, selecting

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

68,

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

69 capability only and

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

70 bit key size.

Do not set the master (certify) key to expire - see Note #3.

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Input any name and email address (it doesn't have to be valid):

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Export the key ID as a variable (

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

71) for use later:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Sign with existing key

(Optional) If you already have a PGP key, you may want to sign the new key with the old one to prove that the new key is controlled by you.

Export your existing key to move it to the working keyring:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Then sign the new key:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Sub-keys

Edit the master key to add sub-keys:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Use 4096-bit RSA keys.

Use a 1 year expiration for sub-keys - they can be renewed using the offline master key. See rotating keys.

Signing

Create a signing key by selecting

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

72 then

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

73:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Encryption

Next, create an encryption key by selecting

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

74:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Authentication

Finally, create an authentication key.

GPG doesn't provide an authenticate-only key type, so select

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

68 and toggle the required capabilities until the only allowed action is

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

76:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Finish by saving the keys.

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Add extra identities

(Optional) To add additional email addresses or identities, use

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

77.

First open the keyring:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Then add the new identity:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

By default, the last identity added will be the primary user ID - use

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

78 to change that.

Verify

List the generated secret keys and verify the output:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Add any additional identities or email addresses you wish to associate using the

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

77 command.

Tip Verify with a OpenPGP key best practice checker:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

The output will display any problems with your key in red text. If everything is green, your key passes each of the tests. If it is red, your key has failed one of the tests.

hokey may warn (orange text) about cross certification for the authentication key. GPG's Signing Subkey Cross-Certification documentation has more detail on cross certification, and gpg v2.2.1 notes "subkey does not sign and so does not need to be cross-certified". hokey may also indicate a problem (red text) with

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

80 on the primary key (see Note #3 about not setting an expiry for the primary key).

Export secret keys

The master key and sub-keys will be encrypted with your passphrase when exported.

Save a copy of your keys:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

On Windows, note that using any extension other than

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

81 or attempting IO redirection to a file will garble the secret key, making it impossible to import it again at a later date:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Revocation certificate

Although we will backup and store the master key in a safe place, it is best practice to never rule out the possibility of losing it or having the backup fail. Without the master key, it will be impossible to renew or rotate subkeys or generate a revocation certificate, the PGP identity will be useless.

Even worse, we cannot advertise this fact in any way to those that are using our keys. It is reasonable to assume this will occur at some point and the only remaining way to deprecate orphaned keys is a revocation certificate.

To create the revocation certificate:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

The

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

82 certificate file should be stored (or printed) in a (secondary) place that allows retrieval in case the main backup fails.

Backup

Once keys are moved to YubiKey, they cannot be moved again! Create an encrypted backup of the keyring on removable media so you can keep it offline in a safe place.

Tip The ext2 filesystem (without encryption) can be mounted on both Linux and OpenBSD. Consider using a FAT32/NTFS filesystem for MacOS/Windows compatibility instead.

As an additional backup measure, consider using a paper copy of the keys. The Linux Kernel Maintainer PGP Guide points out that such printouts are still password-protected. It recommends to write the password on the paper, since it will be unlikely that you remember the original key password that was used when the paper backup was created. Obviously, you need a really good place to keep such a printout.

It is strongly recommended to keep even encrypted OpenPGP private key material offline to deter key overwriting attacks, for example.

Linux

Attach another external storage device and check its label:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

Write it with random data to prepare for encryption:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

Erase and create a new partition table:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

Create a new partition with a 25 Megabyte size:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

Use LUKS to encrypt the new partition. Generate a different password which will be used to protect the filesystem:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

Mount the partition:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

Create an ext2 filesystem:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

Mount the filesystem and copy the temporary GnuPG directory with keyring:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

Optional Backup the OneRNG package:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

Note If you plan on setting up multiple keys, keep the backup mounted or remember to terminate the gpg process before saving.

Unmount, close and disconnect the encrypted volume:

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

OpenBSD

Attach a USB disk and determine its label:

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

Print the existing partitions to make sure it's the right device:

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

Initialize the disk by creating an

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

83 partition with FS type

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

84 and size of 25 Megabytes:

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

Encrypt with bioctl:

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

Create an

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

85 partition on the new crypto volume and the filesystem:

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

Mount the filesystem and copy the temporary directory with the keyring:

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

Note If you plan on setting up multiple keys, keep the backup mounted or remember to terminate the gpg process before saving.

Otherwise, unmount and disconnect the encrypted volume:

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

See OpenBSD FAQ#14 for more information.

Export public keys

Important Without the public key, you will not be able to use GPG to encrypt, decrypt, nor sign messages. However, you will still be able to use YubiKey for SSH authentication.

Create another partition on the removable storage device to store the public key, or reconnect networking and upload to a key server.

Linux

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

OpenBSD

$ dmesg | tail -n2
sd2 at scsibus4 targ 1 lun 0: <TS-RDF5, SD Transcend, TS3A> SCSI4 0/direct removable serial.0000000000000
sd2: 15193MB, 512 bytes/sector, 31116288 sectors

$ doas dd if=debian-live-*-amd64-xfce.iso of=/dev/rsd2c bs=4m
465+1 records in
465+1 records out
1951432704 bytes transferred in 139.125 secs (14026448 bytes/sec)

Windows

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Keyserver

(Optional) Upload the public key to a public keyserver:

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

After some time, the public key will propagate to other servers.

Configure Smartcard

Plug in a YubiKey and use GPG to configure it as a smartcard:

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Enter administrative mode:

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Note If the card is locked, see Reset.

Windows

Use the YubiKey Manager application (note, this is not the similarly named older YubiKey NEO Manager) to enable CCID functionality.

Enable KDF

Key Derived Function (KDF) enables YubiKey to store the hash of PIN, preventing the PIN from being passed as plain text. Note that this requires a relatively new version of GnuPG to work, and may not be compatible with other GPG clients (notably mobile clients). These incompatible clients will be unable to use the YubiKey GPG functions as the PIN will always be rejected. If you are not sure you will only be using your YubiKey on supported platforms, it may be better to skip this step.

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Change PIN

The GPG interface is separate from other modules on a Yubikey such as the PIV interface. The GPG interface has its own PIN, Admin PIN, and Reset Code - these should be changed from default values!

Entering the user PIN incorrectly three times will cause the PIN to become blocked; it can be unblocked with either the Admin PIN or Reset Code.

Entering the Admin PIN or Reset Code incorrectly three times destroys all GPG data on the card. The Yubikey will have to be reconfigured.

NameDefault ValueUsePIN

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

58decrypt and authenticate (SSH)Admin PIN

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

59reset PIN, change Reset Code, add keys and owner informationReset codeNonereset PIN (more information)

Values are valid up to 127 ASCII characters and must be at least 6 (PIN) or 8 (Admin PIN, Reset Code) characters. See the GnuPG documentation on Managing PINs for details.

To update the GPG PINs on the Yubikey:

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Note The number of retry attempts can be changed later with the following command, documented here:

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Set information

Some fields are optional.

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Transfer keys

Important Transferring keys to YubiKey using

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

88 is a destructive, one-way operation only. Make sure you've made a backup before proceeding:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

88 converts the local, on-disk key into a stub, which means the on-disk copy is no longer usable to transfer to subsequent security key devices or mint additional keys.

Previous GPG versions required the

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

90 command before selecting keys. The currently selected key(s) are indicated with an

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

91. When moving keys only one key should be selected at a time.

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Signing

You will be prompted for the master key passphrase and Admin PIN.

Select and transfer the signature key.

$ sudo apt update ; sudo apt -y upgrade

$ sudo apt -y install wget gnupg2 gnupg-agent dirmngr cryptsetup scdaemon pcscd secure-delete hopenpgp-tools yubikey-personalization

Encryption

Type

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

92 again to de-select and

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

93 to select the next key:

$ sudo apt -y install libssl-dev swig libpcsclite-dev

Authentication

Type

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

93 again to deselect and

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

95 to select the last key:

$ sudo apt -y install libssl-dev swig libpcsclite-dev

Save and quit:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Verify card

Verify the sub-keys have been moved to YubiKey as indicated by

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

96:

$ sudo apt -y install libssl-dev swig libpcsclite-dev

Multiple YubiKeys

To provision additional security keys, restore the master key backup and repeat the Configure Smartcard procedure.

$ sudo apt -y install libssl-dev swig libpcsclite-dev

Switching between two or more Yubikeys

When you add a GPG key to a Yubikey using the keytocard command, GPG deletes the key from your keyring and adds a stub pointing to that exact Yubikey (the stub identifies the GPG KeyID and the Yubikey's serial number).

However, when you do this same operation for a second Yubikey, the stub in your keyring is overwritten by the keytocard operation and now the stub points to your second Yubikey. Adding more repeats this overwriting operation.

In other words, the stub will point ONLY to the LAST Yubikey written to.

When using GPG key operations with the GPG key you placed onto the Yubikeys, GPG will request a specific Yubikey asking that you insert a Yubikey with a given serial number (referenced by the stub). GPG will not recognise another Yubikey with a different serial number without manual intervention.

You can force GPG to scan the card and re-create the stubs to point to another Yubikey.

Having created two (or more Yubikeys) with the same GPG key (as described above) where the stubs are pointing to the second Yubikey:

Insert the first Yubikey (which has a different serial number) and run the following command:

$ sudo apt -y install libssl-dev swig libpcsclite-dev

GPG will then scan your first Yubikey for GPG keys and recreate the stubs to point to the GPG keyID and Yubikey Serial number of this first Yubikey.

To return to using the second Yubikey just repeat (insert other Yubikey and re-run command).

Obviously this command is not easy to remember so it is recommended to either create a script or a shell alias to make this more user friendly.

Cleanup

Before finishing the setup, ensure you have done the following:

Saved encryption, signing and authentication sub-keys to YubiKey (

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

97 should show

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

96 for sub-keys).

Saved the YubiKey user and admin PINs which are different and were changed from default values.
Saved the password to the GPG master key in a secure, long-term location.
Saved a copy of the master key, sub-keys and revocation certificate on an encrypted volume, to be stored offline.
Saved the password to that LUKS-encrypted volume in a secure, long-term location (separate from the device itself).
Saved a copy of the public key somewhere easily accessible later.

Now reboot or securely delete

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

99 and remove the secret keys from the GPG keyring:

$ sudo apt -y install libssl-dev swig libpcsclite-dev

Important Make sure you have securely erased all generated keys and revocation certificates if an ephemeral enviroment was not used!

Using keys

Download drduh/config/gpg.conf:

$ sudo apt -y install libssl-dev swig libpcsclite-dev

Install the required packages and mount the non-encrypted volume created earlier:

Linux

$ sudo apt -y install libssl-dev swig libpcsclite-dev

OpenBSD

$ sudo apt -y install libssl-dev swig libpcsclite-dev

Import the public key file:

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

Or download the public key from a keyserver:

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

Edit the master key to assign it ultimate trust by selecting

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

00 and

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

01:

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

Remove and re-insert YubiKey and verify the status:

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

02 indicates the master key is not available (as it should be stored encrypted offline).

Note If you see

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

03 in the output instead - go back and import the public key using the previous step.

Encrypt a message to your own key (useful for storing password credentials and other data):

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

To encrypt to multiple recipients (or to multiple keys):

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

Decrypt the message:

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

Sign a message:

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

Verify the signature:

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

Use a shell function to make encrypting files easier:

$ sudo apt -y install python3-pip python3-pyscard

$ pip3 install PyOpenSSL

$ pip3 install yubikey-manager

$ sudo service pcscd start

$ ~/.local/bin/ykman openpgp info

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

Rotating keys

PGP does not provide forward secrecy - a compromised key may be used to decrypt all past messages. Although keys stored on YubiKey are difficult to steal, it is not impossible - the key and PIN could be taken, or a vulnerability may be discovered in key hardware or the random number generator used to create them, for example. Therefore, it is good practice to occassionally rotate sub-keys.

When a sub-key expires, it can either be renewed or replaced. Both actions require access to the offline master key. Renewing sub-keys by updating their expiration date indicates you are still in possession of the offline master key and is more convenient.

Replacing keys, on the other hand, is less convenient but more secure: the new sub-keys will not be able to decrypt previous messages, authenticate with SSH, etc. Contacts will need to receive the updated public key and any encrypted secrets need to be decrypted and re-encrypted to new sub-keys to be usable. This process is functionally equivalent to "losing" the YubiKey and provisioning a new one. However, you will always be able to decrypt previous messages using the offline encrypted backup of the original keys.

Neither rotation method is superior and it's up to personal philosophy on identity management and individual threat model to decide which one to use, or whether to expire sub-keys at all. Ideally, sub-keys would be ephemeral: used only once for each encryption, signing and authentication event, however in practice that is not really feasible nor worthwhile with YubiKey. Advanced users may want to dedicate an offline device for more frequent key rotations and ease of provisioning.

Setup environment

To renew or rotate sub-keys, follow the same process as generating keys: boot to a secure environment, install required software and disconnect networking.

Connect the offline secret storage device with the master keys and identify the disk label:

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

Decrypt and mount the offline volume:

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

Import the master key and configuration to a temporary working directory. Note that Windows users should import mastersub.gpg:

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

Edit the master key:

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

Renewing sub-keys

Renewing sub-keys is simpler: you do not need to generate new keys, move keys to the YubiKey, or update any SSH public keys linked to the GPG key. All you need to do is to change the expiry time associated with the public key (which requires access to the master key you just loaded) and then to export that public key and import it on any computer where you wish to use the GPG (as distinct from the SSH) key.

To change the expiration date of all sub-keys, start by selecting all keys:

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

Then, use the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

04 command to set a new expiration date. (Despite the name, this will not cause currently valid keys to become expired.)

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

Follow these prompts to set a new expiration date, then

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

05 to save your changes.

Next, export the public key:

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

Transfer that public key to the computer from which you use your GPG key, and then import it with:

$ sudo dnf install wget
$ wget https://github.com/rpmsphere/noarch/raw/master/r/rpmsphere-release-34-2.noarch.rpm
$ sudo rpm -Uvh rpmsphere-release*rpm

$ sudo dnf install gnupg2 dirmngr cryptsetup gnupg2-smime pcsc-tools opensc pcsc-lite secure-delete pgp-tools yubikey-personalization-gui

This will extend the validity of your GPG key and will allow you to use it for SSH authorization. Note that you do not need to update the SSH public key located on remote servers.

Rotating keys

Rotating keys is more a bit more involved. First, follow the original steps to generate each sub-key. Previous sub-keys may be kept or deleted from the identity.

Finish by exporting new keys:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Copy the new temporary working directory to encrypted offline storage, which should still be mounted:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

There should now be at least two versions of the master and sub-keys backed up:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Unmount and close the encrypted volume:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Export the updated public key:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Disconnect the storage device and follow the original steps to transfer new keys (4, 5 and 6) to the YubiKey, replacing existing ones. Reboot or securely erase the GPG temporary working directory.

Adding notations

Notations can be added to user ID(s) and can be used in conjunction with Keyoxide to create OpenPGP identity proofs.

Adding notations requires access to the master key so we can follow the setup instructions taken from this section of this guide.

Please note that there is no need to connect the Yubikey to the setup environment and that we do not need to generate new keys, move keys to the YubiKey, or update any SSH public keys linked to the GPG key.

After having completed the environment setup, it is possible to follow any of the guides listed under "Adding proofs" in the Keyoxide "Guides" page up until the notation is saved using the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

05 command.

At this point the public key can be exported:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

The public key can now be transferred to the computer where the GPG key is used and it is imported with:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

N.B.: The

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

07 command can be issued to ensure that the notions were correctly added.

It is now possible to continue following the Keyoxide guide and upload the key to WKD or to keys.openpgp.org.

SSH

Tip If you want to use a YubiKey for SSH only (and don't really care about PGP/GPG), then since OpenSSH v8.2 you alternatively can simply

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

08 (without requiring anything else from this guide!), as explained in this guide. Yubico also recently announced support for resident ssh keys under OpenSSH 8.2+ on their blue "security key 5 nfc" as mentioned in their blog post._

gpg-agent supports the OpenSSH ssh-agent protocol (

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

09), as well as Putty's Pageant on Windows (

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

10). This means it can be used instead of the traditional ssh-agent / pageant. There are some differences from ssh-agent, notably that gpg-agent does not cache keys rather it converts, encrypts and stores them - persistently - as GPG keys and then makes them available to ssh clients. Any existing ssh private keys that you'd like to keep in

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11 should be deleted after they've been imported to the GPG agent.

When importing the key to

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11, you'll be prompted for a passphrase to protect that key within GPG's key store - you may want to use the same passphrase as the original's ssh version. GPG can both cache passphrases for a determined period (ref.

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11's various

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

14 options), and since version 2.1 can store and fetch passphrases via the macOS keychain. Note than when removing the old private key after importing to

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11, keep the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

16 key file around for use in specifying ssh identities (e.g.

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

17).

Probably the biggest thing missing from

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11's ssh agent support is being able to remove keys.

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

19 have no effect. Instead, you need to use the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

20 utility to lookup a key's keygrip, match that with the desired ssh key fingerprint (as an MD5) and then delete that keygrip. The gnupg-users mailing list has more information.

Create configuration

Create a hardened configuration for gpg-agent by downloading drduh/config/gpg-agent.conf:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Important The

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

14 options do NOT apply when using a YubiKey as a smartcard as the PIN is cached by the smartcard itself. Therefore, in order to clear the PIN from cache (smartcard equivalent to

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

22 and

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

23), you need to unplug the YubiKey, or set the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

24 flag when editing the card to be prompted for the PIN each time.

Tip Set

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

25 for a GUI-based prompt. If the pinentry graphical dialog doesn't show and you get this error:

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

26, you may need to install the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

27 package and restart the computer for the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

28 user session to be fully inherited; this is because behind the scenes,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

29 complains about

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

30, falls back to

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

31 but doesn't find the expected

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

32.

On macOS, use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

33 and set the program path to

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

34 for Intel Macs,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

35 for ARM/Apple Silicon Macs or

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

36 if using MacGPG Suite.

Replace agents

To launch

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11 for use by SSH, use the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

38 or

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

39 commands.

Add these to the shell

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

40 file:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

On modern systems,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

41 will automatically set

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

42 to the correct value and is better than hard-coding to

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

43, if available:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

If you use fish, the correct lines for your

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

44 would look like this (consider putting them into the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

45 block depending on your use case):

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Note that if you use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

46 for ssh-agent forwarding,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

42 only needs to be set on the local laptop (workstation), where the YubiKey is plugged in. On the remote server that we SSH into,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

48 will automatically set

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

42 to something like

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

50 when we connect. We therefore do NOT manually set

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

42 on the server - doing so would break SSH Agent Forwarding.

If you use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

52 (see SSH Agent Forwarding for more info),

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

42 should also be set on the remote. However,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

54 should not be set on the remote, explanation specified in that section.

Copy public key

Note It is not necessary to import the corresponding GPG public key in order to use SSH.

Copy and paste the output from

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

55 to the server's

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

56 file:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

(Optional) Save public key for identity file configuration

By default, SSH attempts to use all the identities available via the agent. It's often a good idea to manage exactly which keys SSH will use to connect to a server, for example to separate different roles or to avoid being fingerprinted by untrusted ssh servers. To do this you'll need to use the command line argument

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

57 or the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

58 and

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

59 options in

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

60.

The argument provided to

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

58 is traditionally the path to the private key file (for example

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

62). For the YubiKey - indeed, in general for keys stored in an ssh agent -

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

58 should point to the public key file,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

48 will select the appropriate private key from those available via the ssh agent. To prevent

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

48 from trying all keys in the agent use the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

66 option along with one or more

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

67 or

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

58 options for the target host.

To reiterate, with

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

66,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

48 will not automatically enumerate public keys loaded into

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

71 or

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11. This means

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

73 authentication will not proceed unless explicitly named by

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

74 or in

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

60 on a per-host basis.

In the case of YubiKey usage, to extract the public key from the ssh agent:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Then you can explicitly associate this YubiKey-stored key for used with a host,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

76 for example, as follows:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Connect with public key authentication

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Tip To make multiple connections or securely transfer many files, consider using the ControlMaster ssh option. Also see drduh/config/ssh_config.

Import SSH keys

If there are existing SSH keys that you wish to make available via

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11, you'll need to import them. You should then remove the original private keys. When importing the key,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11 uses the key's filename as the key's label; this makes it easier to follow where the key originated from. In this example, we're starting with just the YubiKey's key in place and importing

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

79:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

When invoking

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

55, it will prompt for the SSH key's passphrase if present, then the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

29 program will prompt and confirm for a new passphrase to use to encrypt the converted key within the GPG key store.

The migrated key will be listed in

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

82:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Or to show the keys with MD5 fingerprints, as used by

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

20's

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

84 and

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

85 commands:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

When using the key

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

29 will be invoked to request the key's passphrase. The passphrase will be cached for up to 10 minutes idle time between uses, to a maximum of 2 hours.

Remote Machines (SSH Agent Forwarding)

Note SSH Agent Forwarding can add additional risk - proceed with caution!

There are two methods for ssh-agent forwarding, one is provided by OpenSSH and the other is provided by GnuPG.

The latter one may be more insecure as raw socket is just forwarded (not like

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

87 with only limited functionality; if

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

46 implemented by OpenSSH is just forwarding the raw socket, then they are insecure to the same degree). But for the latter one, one convenience is that one may forward once and use this agent everywhere in the remote. So again, proceed with caution!

For example,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

89 does not have some environment variables like

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

90 when you ssh into remote and attach an old

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

89 session. In this case if you use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

46, you need to find the socket manually and

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

93 for each shell. But with

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

52 in fixed place, one can just use it as ssh-agent in their shell rc file.

Use ssh-agent

In the above steps, you have successfully configured a local ssh-agent.

You should now be able to use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

95 on the local machine to log into remote, and should then be able to use YubiKey as if it were connected to the remote machine. For example, using e.g.

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

82 on that remote machine should show the public key from the YubiKey (note

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

97). (If you don't want to have to remember to use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

98, you can use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

99 in

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

00. As a security best practice, always use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

99 only for a single

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

02, never for all servers.)

Use S.gpg-agent.ssh

First you need to go through Remote Machines (GPG Agent Forwarding), know the conditions for gpg-agent forwarding and know the location of

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

52 on both the local and the remote.

You may use the command:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Then in your

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

60 add one sentence for that remote

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

After successfully ssh into the remote, you should check that you have

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

05 lying there.

Then in the remote you can type in command line or configure in the shell rc file with:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

After typing or sourcing your shell rc file, with

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

82 you should find your ssh public key now.

Note In this process no gpg-agent in the remote is involved, hence

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

07 in the remote is of no use. Also pinentry is invoked locally.

Chained SSH Agent Forwarding

If you use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

71 provided by OpenSSH and want to forward it into a third box, you can just

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

09 on the remote.

Meanwhile, if you use

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

52, assume you have gone through the steps above and have

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

52 on the remote, and you would like to forward this agent into a third box, first you may need to configure

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

12 and

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

42 of third in the same way as remote, then in the ssh config of remote, add the following lines

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

You should change the path according to

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

41 on remote and third.

GitHub

You can use YubiKey to sign GitHub commits and tags. It can also be used for GitHub SSH authentication, allowing you to push, pull, and commit without a password.

To configure a signing key:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Make sure the user.email option matches the email address associated with the PGP identity.

Now, to sign commits or tags simply use the

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

15 option. GPG will automatically query YubiKey and prompt you for a PIN.

To authenticate:

Windows

Run the following commands:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

You can then change the repository URL to

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

16 and any authenticated commands will be authorized by YubiKey.

Note If you encounter the error

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

17 - run

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

18 with YubiKey plugged in and try the git command again.

OpenBSD

Install and enable tools for use with PC/SC drivers, cards, readers, then reboot to recognize YubiKey:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Windows

Windows can already have some virtual smartcard readers installed, like the one provided for Windows Hello. To ensure your YubiKey is the correct one used by scdaemon, you should add it to its configuration. You will need your device's full name. To find your device's full name, plug in your YubiKey and open PowerShell to run the following command:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

The name slightly differs according to the model. Thanks to Scott Hanselman for sharing this information.

Create or edit

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

19 to add:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Create or edit

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

20 to add:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Open a command console, restart the agent:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Enter

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

21 to see YubiKey details.

Import the public key:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Trust the master key

Retrieve the public key id:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Export the SSH key from GPG:

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Copy this key to a file for later use. It represents the public SSH key corresponding to the secret key on the YubiKey. You can upload this key to any server you wish to SSH into.

Create a shortcut that points to

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

38 and place it in the startup folder

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

26 to make sure the agent starts after a system shutdown. Modify the shortcut properties so it starts in a "Minimized" window, to avoid unnecessary noise at startup.

Now you can use PuTTY for public key SSH authentication. When the server asks for public key verification, PuTTY will forward the request to GPG, which will prompt you for a PIN and authorize the login using YubiKey.

WSL

The goal here is to make the SSH client inside WSL work together with the Windows agent you are using (gpg-agent.exe in our case). Here is what we are going to achieve:

Note this works only for SSH agent forwarding. Real GPG forwarding (encryption/decryption) is actually not supported. See weasel-pageant for further information or consider using wsl2-ssh-pageant which supports both SSH and GPG agent forwarding.

Use ssh-agent or use S.weasel-pegant

One way to forward is just

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

98 (still need to eval weasel to setup local ssh-agent), and only relies on OpenSSH. In this track,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

46 and

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

29 in ssh/sshd config may be involved; However, if you use the other way (gpg ssh socket forwarding), you should not enable

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

46 in ssh config. See SSH Agent Forwarding for more info.

Another way is to forward the gpg ssh socket, as described below.

Prerequisites

Ubuntu 16.04 or newer for WSL
Kleopatra
Windows configuration

WSL configuration

Download or clone weasel-pageant.

Add

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

31 to shell rc file. Use a named socket here so it can be used in the

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

32 directive of

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

00. Source it with

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

34.

Display the SSH key with

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Edit

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

00 to add the following for each host you want to use agent forwarding:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Note The remote SSH socket path can be found with

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

Remote host configuration

You may have to add the following to the shell rc file.

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Add the following to

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

38:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

And reload the SSH daemon (e.g.,

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

39).

Unplug YubiKey, disconnect or reboot. Log back into Windows, open a WSL console and enter

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

82 - you should see nothing.

Plug in YubiKey, enter the same command to display the ssh key.

Log into the remote host, you should have the pinentry dialog asking for the YubiKey pin.

On the remote host, type

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

82 - if you see the ssh key, that means forwarding works!

Note Agent forwarding may be chained through multiple hosts - just follow the same protocol to configure each host. You may also read this part on chained ssh agent forwarding.

macOS

To use gui applications on macOS, a little bit more setup is needed.

Create

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

42 with the following contents:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Create

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

43 with the following contens:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

You will need to either reboot, or log out and log back in, in order to activate these changes.

Remote Machines (GPG Agent Forwarding)

This section is different from ssh-agent forwarding in SSH as gpg-agent forwarding has a broader usage, not only limited to ssh.

To use YubiKey to sign a git commit on a remote host, or signing email/decrypt files on a remote host, configure and use GPG Agent Forwarding. To ssh through another network, especially to push to/pull from GitHub using ssh, see Remote Machines (SSH Agent forwarding) for more info.

To do this, you need access to the remote machine and the YubiKey has to be set up on the host machine.

After gpg-agent forwarding, it is nearly the same as if YubiKey was inserted in the remote. Hence configurations except

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

07 for the remote can be the same as those for the local.

Important

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

07 for the remote is of no use, hence

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

46 is of no use too for the remote. The mechanism is that after forwarding, remote

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

47 directly communicates with

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

48 without starting

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11 on the remote.

On the remote machine, edit

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

38 to set

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Optional If you do not have root access to the remote machine to edit

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

38, you will need to remove the socket (located at

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

53) on the remote machine before forwarding works. For example,

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

54. Further information can be found on the AgentForwarding GNUPG wiki page.

Import public keys to the remote machine. This can be done by fetching from a keyserver. On the local machine, copy the public keyring to the remote machine:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

On modern distributions, such as Fedora 30, there is typically no need to also set

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

32 in

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

00 as detailed in the next chapter, because the right thing happens automatically.

If any error happens (or there is no

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

57 in the remote) for modern distributions, you may go through the configuration steps in the next section.

Steps for older distributions

On the local machine, run:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

This should return a path to agent-extra-socket -

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

58 - though on older Linux distros (and macOS) it may be

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Find the agent socket on the remote machine:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

This should return a path such as

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

Finally, enable agent forwarding for a given machine by adding the following to the local machine's ssh config file

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

00 (your agent sockets may be different):

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

If you're still having problems, it may be necessary to edit

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

07 file on the local machines to add the following information:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Note The pinentry program starts on local machine, not remote. Hence when there are needs to enter the pin you need to find the prompt on the local machine.

Important Any pinentry program except

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

63 or

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

64 may be used. This is because local

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11 may start headlessly (By systemd without

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

46 set locally telling which tty it is on), thus failed to obtain the pin. Errors on the remote may be misleading saying that there is IO Error. (Yes, internally there is actually an IO Error since it happens when writing to/reading from tty while finding no tty to use, but for end users this is not friendly.)

See Issue #85 for more information and troubleshooting.

Chained GPG Agent Forwarding

Assume you have gone through the steps above and have

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

48 on the remote, and you would like to forward this agent into a third box, first you may need to configure

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

12 of third in the same way as remote, then in the ssh config of remote, add the following lines:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

You should change the path according to

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

69 on remote and third.

Note On local you have

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

87 whereas on remote and third, you only have

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

48.

Using Multiple Keys

To use a single identity with multiple YubiKeys - or to replace a lost card with another - issue this command to switch keys:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Alternatively, use a script to delete the GnuPG shadowed key, where the card serial number is stored (see GnuPG #T2291):

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

See discussion in Issues #19 and #112 for more information and troubleshooting steps.

Require touch

Note This is not possible on YubiKey NEO.

By default, YubiKey will perform encryption, signing and authentication operations without requiring any action from the user, after the key is plugged in and first unlocked with the PIN.

To require a touch for each key operation, install YubiKey Manager and recall the Admin PIN:

Note Older versions of YubiKey Manager use

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

72 instead of

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

73 in the following commands.

Authentication:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Signing:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Encryption:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Depending on how the YubiKey is going to be used, you may want to look at the policy options for each of these and adjust the above commands accordingly. They can be viewed with the following command:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

If the YubiKey is going to be used within an email client that opens and verifies encrypted mail,

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

74 or

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

75 may be desirable.

YubiKey will blink when it is waiting for a touch. On Linux you can also use yubikey-touch-detector to have an indicator or notification that YubiKey is waiting for a touch.

GPG keys on YubiKey can be used with ease to encrypt and/or sign emails and attachments using Thunderbird, Enigmail and Mutt. Thunderbird supports OAuth 2 authentication and can be used with Gmail. See this guide from EFF for detailed instructions. Mutt has OAuth 2 support since version 2.0.

Mailvelope

Mailvelope allows GPG keys on YubiKey to be used with Gmail and others.

Important Mailvelope does not work with the

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

76 option set in

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

77.

On macOS, install gpgme using Homebrew:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

To allow Chrome to run gpgme, edit

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

78 and add:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Edit the default path to allow Chrome to find GPG:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Finally, install the Mailvelope extension from the Chrome app store.

Mutt

Mutt has both CLI and TUI interfaces, and the latter provides powerful functions for daily email processing. In addition, PGP can be integrated such that signing/encryption/verifying/decryption can be done without leaving TUI.

To enable GnuPG support, one can just use the config file

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

79 provided by mutt, usually located at

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

80 after installation. One only needs to edit the file on options like

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

81,

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

82 and

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

83. After editting one can

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

84 this rcfile in their main

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

85 to use it.

Important If one uses

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

63 as one's pinentry program in

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

07, it would mess with one's Mutt TUI, as reported. This is because Mutt TUI uses curses while tty output may harm the format. It is recommended to use

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

64 or other graphic pinentry program.

Reset

If PIN attempts are exceeded, the card is locked and must be reset and set up again using the encrypted backup.

Copy the following script to a file and run

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

89 to lock and terminate the card. Then re-insert YubiKey to reset.

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Or use

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

63 (sometimes in

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

91):

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Recovery after reset

If for whatever reason you need to reinstate your YubiKey from your master key backup (such as the one stored on an encrypted USB described in Backup), follow the following steps in Rotating keys to setup your environment, and then follow the steps of again Configure Smartcard.

Before you unmount your backup, ask yourself if you should make another one just in case.

Notes

YubiKey has two configurations: one invoked with a short press, and the other with a long press. By default, the short-press mode is configured for HID OTP - a brief touch will emit an OTP string starting with
```
$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso
```
92. If you rarely use the OTP mode, you can swap it to the second configuration via the YubiKey Personalization tool. If you never use OTP, you can disable it entirely using the YubiKey Manager application (note, this not the similarly named older YubiKey NEO Manager).
Programming YubiKey for GPG keys still lets you use its other configurations - U2F, OTP and static password modes, for example.
Setting an expiry essentially forces you to manage your subkeys and announces to the rest of the world that you are doing so. Setting an expiry on a primary key is ineffective for protecting the key from loss - whoever has the primary key can simply extend its expiry period. Revocation certificates are better suited for this purpose. It may be appropriate for your use case to set expiry dates on subkeys.

To switch between two or more identities on different keys - unplug the first key and restart gpg-agent, ssh-agent and pinentry with

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

93, then plug in the other key and run

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

94 - then it should be ready for use.

To use yubikeys on more than one computer with gpg: After the initial setup, import the public keys on the second workstation. Confirm gpg can see the card via

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

18, Trust the public keys you imported ultimately (as above). At this point

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

96 should show your (trusted) key.

Troubleshooting

Use

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

97 to understand GPG options and command-line flags.

To get more information on potential errors, restart the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11 process with debug output to the console with

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

99.

If you encounter problems connecting to YubiKey with GPG - try unplugging and re-inserting YubiKey, and restarting the
```
$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
```
11 process.

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

01 - you likely need to install GnuPG version 2.x. Another possibility is that there is a problem with the PIN, e.g. it is too short or blocked.

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

02 - make sure the YubiKey is inserted correctly. It should blink once when plugged in.

If you still receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

02 - you likely need to install newer versions of yubikey-personalize as outlined in Required software.

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

04 - YubiKey is likely locked. Install and run yubikey-personalization-gui to unlock it.

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

05 - you likely need to use 2048 bit RSA key sizes.

If you receive the error,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

26 - make sure you replaced

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

71 with

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

11 as noted above.

If you still receive the error,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

26 - run the command

$ grep $(sha512sum debian-live-*-amd64-xfce.iso) SHA512SUMS
SHA512SUMS:f9976e2090a54667a26554267941792c293628cceb643963e425bf90449e3c0eeb616e8ededc187070910401c8ab0348fdbc3292b6d04e29dcfb472ac258a542  debian-live-11.6.0-amd64-xfce.iso

If you still receive the error,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

26 - edit

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

12 to set a valid

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

29 program path, e.g.

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

34 on macOS.

If you still receive the error,

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

26 - it is a known issue that openssh 8.9p1 and higher has issues with YubiKey. Adding

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

16 to

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

17 often resolves the issue.

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

18 from

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

19, make sure you have installed and started

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

20.

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

21 from

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

19, the UNIX file socket that the agent uses for communication with other processes may not be set up correctly. On Debian, try

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

23. Also see that

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

41 is returning single path, to existing

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

52 socket.

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

26, increase ssh verbosity with the

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

27 flag and ensure the public key from the card is being offered:

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

28. If it is, ensure you are connecting as the right user on the target system, rather than as the user on the local system. Otherwise, be sure

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

59 is not enabled for this host.

If SSH authentication still fails - add up to 3

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

27 flags to the

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

48 client to increase verbosity.

If it still fails, it may be useful to stop the background

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

32 daemon process service on the server (e.g. using

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

33) and instead start it in the foreground with extensive debugging output, using

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

34. Note that the server will not fork and will only process one connection, therefore has to be re-started after every

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

48 test.

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

36 see using of multiple keys.

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

37 or

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

38 use

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

39 to set

$ gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B

00 to

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

41.

If, when you try the above

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

42 command, you get the error

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

43 - manually specify trust for the key in

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

44 by using the

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

45 directive.

If, when using a previously provisioned YubiKey on a new computer with

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

46, you see the following error on

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

47, you need to adjust the trust associated with the key. See the note above.

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

If you receive the error,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

48,

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

49, or

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

38 the sub-key may be expired and can no longer be used to encrypt nor sign messages. It can still be used to decrypt and authenticate, however.

If you lost your GPG public key, follow this guide to recover it from YubiKey.
Refer to Yubico article Troubleshooting Issues with GPG for additional guidance.

Alternatives

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

51 is an SSH and GPG agent which you can use with your PIV hardware security device (e.g. a Yubikey).

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

52 is an option to use GnuPG with TPM systems.

Create keys with batch

Keys can also be generated using template files and the

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

53 parameter - see GnuPG documentation.

Start from the gen-params-rsa4096 template. If you're using GnuPG v2.1.7 or newer, you can also use the (gen-params-ed25519 template. These templates will not set the master key to expire - see Note #3.

Generate master key:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

Verify the result:

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyring.debian.org --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

$ gpg --verify SHA512SUMS.sign SHA512SUMS
gpg: Signature made Sat 17 Dec 2022 11:06:20 AM PST
gpg:                using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B

The key fingerprint (

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

54) will be used to create the three subkeys for signing, authentication and encryption.

Now create the three subkeys for signing, authentication and encryption. Use a 1 year expiration for sub-keys - they can be renewed using the offline master key, see rotating keys.

We will use the the quick key manipulation interface of GNUPG (with

$ sudo dmesg | tail
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS3A PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk

$ sudo dd if=debian-live-*-amd64-xfce.iso of=/dev/sdb bs=4M status=progress ; sync
465+1 records in
465+1 records out
1951432704 bytes (2.0 GB, 1.8 GiB) copied, 42.8543 s, 45.5 MB/s

55), see the documentation.

What to do if I forgot my Blink password?

Enter the email address associated with your Blink account. Tap Forgot password? in the bottom on the screen. The following message displays, "Please note that changing your password will require you to sign in again on all of your devices, as well as relink your Alexa and IFTTT accounts." Tap OK.

Why can't i log into my Blink account?

There may be a couple of reasons you cannot log in to your Blink account. The most common reason is the email address or password being entered incorrectly. This is common and can be easily fixed. If your Blink app is on a device that uses VPN, please disconnect the VPN to set up your devices.

How do I get into my Blink account?

Open your Blink app and press "I already have an account". You will then need to enter either your email or mobile number that is listed on your account and complete the method of authentication.

How do I change my Blink Internet password?

The whole process of changing your Wi-Fi network name and password can be broken down into four main steps:.

Get your router's IP address..

Change your network settings..

Test your new network configuration..

How do i reset my blink password

Debian and Ubuntu

Fedora

Arch

RHEL7

NixOS

OpenBSD

macOS

Windows

YubiKey

OneRNG

Temporary working directory

Harden configuration

Signing

Encryption

Authentication

Add extra identities

Enable KDF

Change PIN

Set information

Signing

Encryption

Authentication

Switching between two or more Yubikeys

Setup environment

Renewing sub-keys

Rotating keys

Create configuration

Replace agents

Copy public key

(Optional) Save public key for identity file configuration

Connect with public key authentication

Import SSH keys

Remote Machines (SSH Agent Forwarding)

Use ssh-agent

Use S.gpg-agent.ssh

Chained SSH Agent Forwarding

GitHub

OpenBSD

Windows

WSL

Use ssh-agent or use S.weasel-pegant

Prerequisites

WSL configuration

Remote host configuration

macOS

Steps for older distributions

Chained GPG Agent Forwarding

Mailvelope

Mutt

Recovery after reset

Create keys with batch

What to do if I forgot my Blink password?

Why can't i log into my Blink account?

How do I get into my Blink account?

How do I change my Blink Internet password?

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