A 3 minute read.

SSH keys suck. They are a file on the disk and you can easily move it to other
machines instead of storing them in hardware where they can’t be exfiltrated.
Using a password to encrypt the private key is a viable option, but the UX for
that is hot garbage. It’s allegedly the future, so surely we MUST have some way
to make this all better, right?

<Numa> >implying there is a way to make anything
security related better

Luckily, there is actually something we can do for this! As of OpenSSH
8.2 (Feburary 14, 2020) you are
able to store an SSH private key on a yubikey! Here’s how to do it.

<Mara> This should work on other FIDO keys like
Google’s Titan, but we don’t have access to one over here and as such haven’t
tested it. Your mileage may vary. We are told that it works with the Google
Titan key that is handed out to Go contributors.

First install yubikey-manager (see
here for more
information, or run nix-shell -p yubikey-manager to run it without installing
it on NixOS), plug in your yubikey and run ykman list:

$ ykman list
YubiKey 5C NFC (5.4.3) [OTP+FIDO+CCID] Serial: 4206942069

If you haven’t set a PIN for the yubikey yet, follow
this
to set a PIN of your choice. Once you do this, you can generate a new SSH key
with the following command:

ssh-keygen -t ed25519-sk -O resident

<Mara> If that fails, try ecdsa-sk
instead! Some hardware keys may not support storing the key on the key
itself.

Then enter in a super secret password (such as the Tongues you received as a kid
when you were forced into learning the bible against your will) twice and then