I'd like to be able to log into and out of my ssh servers freely without entering a password. Previously, I did this with
ssh-keygen, storing the key file under my
Since I also have an OpenPGP key, I thought it might be nice to have one less private key to keep track of, and use my OpenPGP key for SSH authentication. The documentation is sparse, but after a whole day of fussing with it, I've finally gotten it to work. It appears that a best practice is to create a separate authentication-only subkey for this purpose, so that's what I've done.
The authentication-only subkey can be protected with a password, in which case it's required upon login (which defeats the purpose, convenience-wise). In the interest of extreme convenience (and because my security needs are low atm), I'd like to do without the password altogether.
(I'm aware that
gpg-agent can cache the password for a set amount of time, so that it's not required on subsequent logins, but the question remains:)
What are the theoretical security risks posed by using an authentication-only subkey with no password? Apart from the possibility that my private keys are stolen and someone could use them to log into my SSH servers (or anywhere else I have authorized it), is there any way that using a passwordless authentication-only subkey might compromise the security of my other subkeys, or the originating secret key?