https://rzetterberg.github.io/yubikey-gpg-nixos.html PGP, or Pretty Good Privacy, is a popular encryption protocol. I use my PGP key to manage secrets via git-crypt and to sign emails https://wiki.debian.org/Subkeys?action=show&redirect=subkeys <button class="pull-url autopull" value="https://wiki.debian.org/Subkeys?action=show&redirect=subkeys">pull</button> the best guide to key management that i've found: reference this when creating more subkeys https://security.stackexchange.com/questions/29851/how-many-openpgp-keys-should-i-make brief guide that had a link to the thread