Configuring Yubikeys for SSH Authentication
This document explains how to configure a Yubikey for SSH authentication
Install Yubikey Personalization Tool and Smart Card Daemon
[email protected]:~$ sudo apt install -y yubikey-personalization scdaemon
First, you’ll need to ensure that your system is fully up-to-date.
[email protected]:~$ pcsc_scan Scanning present readers... Reader 0: Yubico Yubikey 4 OTP+U2F+CCID 00 00 Card state: Card inserted, Possibly identified card (using /usr/share/pcsc/smartcard_list.txt): Yubico Yubikey 4 OTP+CCID
In order for our Yubikey to be detected as a smart card, we’ll need to set our Yubikey to CCID mode.
[email protected]:~$ sudo ykpersonalize -m 86 The USB mode will be set to: 0x86 Commit? (y/n) [n]: y
After this modification, GPG should now be able to recognize our Yubikey as a smart card.
[email protected]:~$ gpg --card-status Reader ...........: Yubico Yubikey 4 OTP U2F CCID 00 00 Version ..........: 2.1 Manufacturer .....: Yubico Key attributes ...: rsa2048 rsa2048 rsa2048 Max. PIN lengths .: 127 127 127 PIN retry counter : 3 0 3
Now we will need to change the default PIN that is configured.
The default PIN is 123456 and default admin PIN is 12345678.
[email protected]:~$ gpg --change-pin gpg: OpenPGP card no. F8482212202010006041587850000 detected 1 - change PIN 2 - unblock PIN 3 - change Admin PIN 4 - set the Reset Code Q - quit Your selection? 1 # Enter a new PIN PIN changed. 1 - change PIN Your selection? 3 # Enter a new admin PIN PIN changed. Your selection? q
Updated on: 2021-Dec-02