gpg: decryption failed: Bad session key

Question

I'm trying to decrypt a file using gpg and getting this error:

$ gpg --no-tty --batch --verbose --decrypt --passphrase foo file.enc
Version: GnuPG v1.4.11 (GNU/Linux)
gpg: armor header: 
gpg: CAST5 encrypted data
gpg: encrypted with 1 passphrase
gpg: decryption failed: Bad session key

I tried to reload the gpg agent, no luck:

$ gpgconf --reload gpg-agent

How to solve that?

Answer 1

For the record, if somebody will encounter this problem, too:

The problem was, that the encryption was done using gpg version 1.4.11 and the decryption was using gpg version 2.0.22.

After upgrading the encryption to gpg2 (2.0.17), everything worked fine.

Answer 2

I found this, which seems to be the magic that I could not find anywhere else:

Try adding --pinentry-mode loopback to your command. Maybe there is a problem with your installation / pinentry program so that it does not start or you are accidentally using a dummy / test pinentry which provides the wrong passphrase.