I know this is a bit weird. I generated ssh keys on my server, but I still want to force clients to enter a passphrase to be able to SSH to the server,even if they have the key. Is that even possible? Can I set a password on top of the key, and force clients to use both to SSH?
Without knowing the version of OpenSSH you're running, or the distro, it's difficult to answer. However, there are many ways to achieve this. One such way, if you're running a recent version of OpenSSH, is to use the
AuthenticationMethods directive in you
/etc/ssh/sshd_config file. Example: