Francois Rousseau wrote:
In addition, is there anything done to create a new attribute that would
also be allowed in a counterSignature attribute in order to effectively
define its scope (e.g. content was or was not verified against the message
digest before generating the countersignature)?
I recall mentioning this as a possible way to make it easier for a
client to know if a countersigner has verified the original content.
There are various other ways of dealing with this which don't need an
additional attribute. One is to treat it in an analagous manner to other
signatures and judge the validity of the certificate based on the
signing authority: or more specifically its policy.
In the case of some timestamping servers the certificates have specific
V3 extensions: extendedKeyUsage. I can't comment on how universal this
is.
In a human readable environment the actual name of the countersigning
authority could help avoid confusion: for example a message saying
"countersigned by 'foobar timestamping authority' on HH:MM".
Steve.
--
Dr Stephen N. Henson. UK based freelance Cryptographic Consultant.
For info see homepage at http://www.drh-consultancy.demon.co.uk/
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