Mailing List Archive: Compatibility with PGP

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Hi

I have been trying to gain backward compatibility with some older
versions of PGP and I installed the rsa and idea extensions over the
week end, so that I could (hopefully) communicate with users of PGP
2.6.x.

I have come across a few problems.

I have a Linux system, and I use Kmail and Geheimnis. Kmail has a PGP
link so I use PGP5.0i to automatically verify and decrypt messages
when they are opened. PGP is buggy and less flexible than GnuPG, so I
use GnuPG to sign and encrypt all of my outgoing messages.
I also have a Windoze system with Eudora and PGP 6.0.2ckt.

This set up has worked very well, and I have had no problem with DH/DSS
keys.

However things do no work so well when using RSA.

I will list the combinations and permutations.

1) RSA Sign.....Signature good on PGP 5.0, 6.0.2, and 2.6.3

2)RSA Encrypt ....Decryption by PGP 5.0, and 6.0.2 but not by 2.6.3

3)RSA Sign and Encrypt...... PGP5.0 decrypts, but can find no signature.
PGP2.6.3 finds a signature but can not
decrypt.
PGP6.0.2. Error Detached signature.
No call back,
Nothing happens.
Needless to say...all functions are OK when GnuPG is used for
signing/encryption/verification/decryption.But then not everyone uses
GnuPG!
Does anyone have any comments or suggestions as to how I can get round
this problem?

Regards
Brian
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Version: GnuPG v0.9.7 (GNU/Linux)
Comment: Made with Geheimnis

iD8DBQE3biI0Ty0aGYyQpX8RAkDfAKDXH4bjZV9EZDyNG8qMUF7/ZWF3HACfbyoG
tEsHZJlX/lDXH3lW7irRDHg=
=IGN2
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--
Brian Galbraith
**************************************************************
Powered by SuSE Linux 6.1
Encrytped mail preferred
I use GnuPG for Linux.
My DSS key 0x8C9OA57F
RSA key 0x6AB8303
may be downloaded from: Idap://certserver.pgp.com
**************************************************************

On Mon, 21 Jun 1999, Brian Galbraith wrote:

> versions of PGP and I installed the rsa and idea extensions over the
> week end, so that I could (hopefully) communicate with users of PGP
> 2.6.x.
>
> I have come across a few problems.

To encrypt in an PGP2.6x compatible format you need the IDEA and RSA
modules (check if you need a license for these patented alogrithms). You
should add the loading of these modules to your GnuPG config file. You can
check if you installed these modules correctly with the command
"gpg --version". In the listing of ciphers and pubkeys their should appear
IDEA and RSA.

To encrypt or sign in PGP 2.6 readable format, use these options to your
gpg commands additionally:

--rfc1991 --cipher-algo idea --digest-algo md5 --compress-algo 1

Please note, PGP2.6 could read the resulting message only if all keys you
used to encrypt or sign are RSA keys. If you use only one none RSA key,
PGP 2.6.x will fail. Further more, you must use files when encrypting or
signing. PGP 2.6 is unable to process files you encrypted or signed using
stdin/stdout with GnuPG.

If you use shells like KMail and/or Geheimnis it may be possible that
these programms use stdin/stdout to feed data to and from GnuPG. So
creating PGP 2.6 compatible messages with these tools is not possible.

cu
Michael