diff --git a/doc/ChangeLog b/doc/ChangeLog index 02cadb8b5..f24a93b4f 100644 --- a/doc/ChangeLog +++ b/doc/ChangeLog @@ -1,3 +1,7 @@ +2002-11-21 David Shaw + + * gpg.sgml: Add an interoperability section. + 2002-11-17 David Shaw * gpg.sgml: Correct defaults for --s2k-mode and --s2k-digest-mode. diff --git a/doc/gpg.sgml b/doc/gpg.sgml index 72c1169bd..45600ee2f 100644 --- a/doc/gpg.sgml +++ b/doc/gpg.sgml @@ -2518,6 +2518,30 @@ command line or using - to specify stdin. + + INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS + +GnuPG tries to be a very flexible implementation of the OpenPGP +standard. In particular, GnuPG implements many of the "optional" +parts of the standard, such as the RIPEMD/160 hash, and the ZLIB +compression algorithms. It is important to be aware that not all +OpenPGP programs implement these optional algorithms and that by +forcing their use via the --cipher-algo, --digest-algo, +--cert-digest-algo, or --compress-algo options in GnuPG, it is +possible to create a perfectly valid OpenPGP message, but one that +cannot be read by the intended recipient. + + + +For example, as of this writing, no version of official PGP supports +the BLOWFISH cipher algorithm. If you use it, no PGP user will be +able to decrypt your message. The same thing applies to the ZLIB +compression algorithm. By default, GnuPG will do the right thing and +create messages that are usable by any OpenPGP program. Only override +this safe default if you know what you are doing. + + + BUGS @@ -2532,4 +2556,3 @@ as locked memory is allocated. -