This is a cheatsheet for some of the most important (to me) gpg commands. Also some notes on the various YubiKey auth possibilities and standards.

Tools

https://developers.yubico.com/Software_Projects/YubiKey_Device_Configuration/

• Yubikey Manager (ykman)
• Yubikey CLI (ykpersonalize)
• Yubico PIV tool (yubico-piv)

Guides

https://github.com/drduh/YubiKey-Guide

List connected YubiKeys

ykman list

Listing the keys on the smartcard

gpg --card-edit

Encryption (asymmetric)

Encrypt

gpg --output doc.gpg --encrypt --recipient stefan.weisser@googlemail.com doc.txt

Decrypt

gpg --output doc.txt2 --decrypt doc.gpg

Encryption (symmetric)

Encrypt

gpg --output doc.gpg --symmetric doc.txt

Decrypt

gpg --output doc.txt2 --decrypt doc.gpg

YubiHSM2

Hardware module.

YubiHSM Auth

YubiHSM Auth is a command-line tool for the YubiKey HSM Auth application. This is used for storing the authentication keys of a YubiHSM in a YubiKey.

PKCS#11

OATH

HOTP TOTP

OTP

Requires YubiCloud to verify

PIV

PIV, or FIPS 201, is a US government standard. It enables RSA or ECC sign/encrypt operations using a private key stored on a smartcard (such as the YubiKey), through common interfaces like PKCS#11.

YubiKey 4 and 5 have 24 slots for storing certificates.

PIV slots explained:

https://developers.yubico.com/PIV/Introduction/Certificate_slots.html

YubiKey and OpenPGP

Default User PIN and Admin PIN for OpenPGP: 123456 and 12345678