Copyright © 1999 by Kyle Hasselbacher
This article is based on an earlier
PGP 2.x/GnuPG
compatability guide written by Kyle Hasselbacher
(<kyle@toehold.com>).
Mike Ashley (<jashley@acm.org>) edited and expanded it.
Michael Fischer v. Mollard (<mfvm@gmx.de>) transformed the
HTML source to DocBook SGML and also expanded it further.
Some of the details described here came from the
gnupg-devel and gnupg-user mailing lists.
The workaround for both signing with and encrypting to an RSA key were
taken from
Gero
Treuner's compatability script.
Please direct questions, bug reports, or suggesstions to
the maintainer, Mike Ashley.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
A copy of the license is included in the section entitled "GNU
Free Documentation License".
This document describes how to communicate with people still using
old versions of PGP 2.x
GnuPG can be used as a nearly complete replacement for
PGP 2.x.
You may encrypt and decrypt PGP 2.x messages using imported
old keys, but you cannot generate PGP 2.x keys.
This document demonstrates how to extend the standard distribution of
GnuPG to support PGP 2.x keys as well as what options must be used to
ensure inter-operation with PGP 2.x users.
It also warns of anomalies
with the interoperation of PGP 2.x and GnuPG.
Note: Using the extension modules
idea.c and rsa.c without
licensing the patented algorithms they implement may be illegal.
I do not recommend you use these modules.
If you have PGP 2.x keys, I suggest you revoke them in favor of new keys and
encourage correspondents who use PGP 2.x keys to do the same.