Adam Shostack <adam@homeport.org> writes:

Are you claiming that S/mime no longer has the enourmous compatability problems it used to have?

It never had much in the way of compatibility problems (see e.g. RSA's S/MIME interop page, if it still exists - even Microsoft's implementation would interoperate without any real trouble). It *did* have a problem that the compatibility was typically at the level of RC2/40. This hasn't been an issue since the export controls were lifted.

Is there any Open source implementation of the protocol?

Well, there's http://www.cs.auckland.ac.nz/~pgut001/cryptlib/index.html for starters, which has been around for some years. Peter.