Alas, there is an algorithmic difference. PGP uses IDEA with 128 bit
session keys. There is currently no way to specify alternate
per-session encryption algorithms in the protocol. IMHO this needs to
be addressed in the next revision of the protocol.
This is incorrect. There is an algorithm byte in the PGP Protocol
that defines the secret-key cypher being used. Currently, the only
defined cypher is IDEA, and as far as I know, no plans are in the
works to support DES (although Triple-DES might be supported in the
future).
Hope this clarifies things.
-derek