Symmetric Encryption Requirement

David Shaw dshaw at
Fri Dec 19 10:41:04 CET 2003

On Fri, Dec 19, 2003 at 10:30:14AM -0500, Mark Jacobs wrote:
> We have a need for either 
> 1) GNUPG needs to be able to Symmetricly encrypt a file with 
> triple DES and write the key used to a separate file (in clear text) 
> and the encrypted data to a different file.
> 2) Strip out the encrypted key from an PGP/GNUPG encrypted file
> and write this key to a different file in clear text.
> Reason, we have files sent to us that have been encrypted by PGP
> using symmetric encryption and we want to be able to decrypt the
> data using mainframe(S/390) based triple DES decryption.

You can get the key with --show-session-key and write it to a file
however you like, but it is unlikely you will be able to decrypt the
data without doing some work, as OpenPGP programs use a special
"OpenPGP cipher feedback mode" which may not be supported by your
generic 3DES implementation.

Why not just run GnuPG on the mainframe?


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