Error Message: Encrypted Session Key is Bad ??

Stefan H. Holek
Mon Jan 14 12:04:01 2002


GnuPG will create a "Symmetrically Encrypted and MDC Packet(tag 18)" for 
the IV16 algos (AES*, TWOFISH). Could it be that your friend's PGP version 
does not support this packet type?

Try the --openpgp option to suppress MDC generation


<plug type=shameless>
Such things can easily be detected using

At 13.01.2002 19:57 -0800, Nick Andriash wrote:
>A friend and I had been exchanging a few encrypted messages the other day,
>and he was unable to decrypt one of the first messages I had sent,
>receiving the error message that the "Encrypted Session Key is Bad". So,
>I re-sent the message a couple of times, changing my preferred Algorithm
>from AES-256 to AES-128 and 3DES, and with both messages he had no
>problem decrypting.
>Why should it matter what Symmetric Algorithm of choice I have listed,
>because when you encrypt _to_ someone, that encryption should use
>whatever Algorithm the _Recipient_ has listed as their preferred
>Algorithm, should it not?