gpg problem: unusable public key

[^rooker]

[PROBLEM]
I wanted to encrypt a file, but gpg gave me the following response:

Code: Select all

gpg: rooker@das-werkstatt.com: skipped: unusable public key
gpg: top-secret.tar.bz2: encryption failed: unusable public key

[SOLUTION]
My key had expired.

Ken Newquist's Blog at Lafayette College showed me the steps to do it. Unfortunately, I still got the same error message

The reason was: My main public key could only sign, and my subkey could encrypt - but was still marked as expired. Thanks to a
post on gnupg.org by Charly Avital, it was trivial to revive my subkey, too.

Now, encryption works fine again!