I used an id_ed25519 key on a Debian Bullseye to connect to our remote servers, which had a passphrase. My laptop crashed so I recovered the key from a backup and started using it on an Ubuntu 22.04. However, it never once asked for my passphrase on Ubuntu, it just simply connected. Now that I have a new laptop, I moved the key back to it, another Debian Bullseye and now it asks for my passphrase again.
Does anyone have an explanation for this? What's the use of a passphrase on an ssh-key when it can just be circumvented by copying it to an Ubuntu machine?
I'm not sure if it matters (in principal it shouldn't), but the passphrase for the ssh-key was the same as the password for my desktop login.
