I have a request to amend the language in 12.1.
Here is the problem:
An implementor wants to be interoperable with PGP 2.6.x and OpenPGP. As you
know, there is a problem that arises that PGP 2.6.x is (usually) IDEA-only,
but OP mandates 3DES.
If a user wants to send a message to someone who uses OP, and 2.6, there's
a no-win there. Section 12.1 says:
An implementation that is striving for backwards compatibility MAY
consider a V3 key with a V3 self-signature to be an implicit
preference for IDEA, and no ability to do TripleDES. This is
technically non-compliant, so if an implementation is forming a
message to be read by a V3 keyholder and a V4 keyholder that does
not speak IDEA, the implementation must somehow break this up into
two messages (which is relatively easy to do for email), or issue an
error message when this is not possible.
It turns out that this is sometimes easier said than done.
Does anyone object to changing this to:
An implementation that is striving for backwards compatibility MAY
consider a V3 key with a V3 self-signature to be an implicit
preference for IDEA, and no ability to do TripleDES. This is
technically non-compliant and depredcated, but an implementation MAY
use either IDEA or TripleDES for interoperability in this situation.
Jon
-----
Jon Callas jon(_at_)pgp(_dot_)com
CTO, Total Network Security 3965 Freedom Circle
Network Associates, Inc. Santa Clara, CA 95054
(408) 346-5860
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