Chris,
To my knowledge, no interoperability testing has been performed of signedData
or envelopedData content types including
ACs. There are no ACs included in the Examples of S/MIME Messages
Internet-Draft. Also, there are no ACs included in the
test messages documented in Jim Schaad's interoperability matrix for RFCs
2630 through 2634 (available from
<http://www.imc.org/ietf-smime/interop-matrix.html>).
Well I've never seen any public examples of attribute certificates in
any context. I've been sent a few in private email (on the understanding
that they weren't redistributed) but so far they've all been broken and
would typically cause an ASN1 parser to choke.
Steve.
--
Dr Stephen N. Henson. http://www.drh-consultancy.demon.co.uk/
Personal Email: shenson(_at_)drh-consultancy(_dot_)demon(_dot_)co(_dot_)uk
Senior crypto engineer, Celo Communications: http://www.celocom.com/
Core developer of the OpenSSL project: http://www.openssl.org/
Business Email: drh(_at_)celocom(_dot_)com PGP key: via homepage.