Gnugpg and PGP 8.1-9.0 compatibility

I was just curious whether GnuGPG and PGP are compatible with each other as far as sending emails. A vendor of ours has pretty much forced us to install some sort of email encryption program in order to communicate with them. They are using PGP 8.1 and I refuse to recommend our company pay for that program for one (out of a few hundred) vendor, but before I go butting my head against this I’m wondering if PGP can only be used to encrypt/decrypt its own emails. Our company is using Office 2003 (I don’t think we’ve upgraded to SP2 which I’ve noticed needs to be done). Not sure what the vendor is using for email client or if it even matters. Any tips or suggestions would be helpful. Thanks in advance.


Both program use the OpenPGP format and thus it should be no problem to exchange encrypted mails from GPG to PGP.

But some things might cause trouble:
GPG does not support the IDEA algorithm and if the
PGP key prefers IDEA, GPG won’t be able to read it.

PGP does not support Blowfish and if the GPG key prefers this algorithm PGP won’t be able to read it.

But with the default settings CAST5/AES no problem should occur.

Thanks Timo,

Maybe it would help if I gave details to the keys being used:

GPG Key-
Type: Key Pair
Key Id: *********
Algorithm: RSA/RSA
Size: 1792/1792 bits
Created: 4/19/2006
Expires: Never
Validity: Full
Cipher: AES

PGP Key-
Type: Public Key
Key ID: *******
Algorith: DSA/ELG
Size: 1024/2048 bits
Created: 12/14/2004
Expires: Never
Validity: Full
Cipher: AES

Thanks for the help!

Hmm, from what I see there should be no problem with the ciphers because it’s always AEs which is supported by GPG/PGP.

Sorry, but without more detailled key information I don’t think I can help you. Maybe it is related to the hash algorithm and/or the compression algorithms.

I’d be happy to provide any information necessary, just let me know what you need (I may need instructions on how to get it though since I’m not that familiar with the programs).
Thanks for your time with this!