GnuPG keys:
- https://alexcabal.com/creating-the-perfect-gpg-keypair/
- https://www.gnupg.org/faq/gnupg-faq.html
- https://wiki.debian.org/Subkeys
Use GnuPG for SSH:
- https://linode.com/docs/security/authentication/gpg-key-for-ssh-authentication/
- https://incenp.org/notes/2015/gnupg-for-ssh-authentication.html
- https://www.hanselman.com/blog/DecodingAnSSHKeyFromPEMToBASE64ToHEXToASN1ToPrimeDecimalNumbers.aspx
Versioning secrets:
Password management with GnuPG: