In <200005221536(_dot_)IAA01210(_at_)finney(_dot_)org>, on 05/22/00
at 09:36 AM, hal(_at_)finney(_dot_)org said:
so is the signing key id the only subpacket that is allowed to go in
the unhashed area?
No, anything which might reasonably be considered to be "advisory" and
not security critical could go there. For example the URL where the cert
can be found. I don't know if there is an exhaustive list. The point is
that the software needs to be aware that material in the unhashed region
is not authenticated and could have been tampered with.
also, for a given subpacket type, can instances of
that subpacket appear in either the hashed subpacket field or the
unhashed subpacket field, or is it a mutually exclusive situation?
I don't see any problem in allowing that.
As an open question to list members:
What do you consider the proper response of OpenPGP software (client &
server) when an established key (ie a key on the server or users keyring)
is "updated" and unhashed data has been changed?
Take the example:
Software A lets the user enter on his key the prefered URL to obtain his
key on the self-sig for his key and the software stores it in an unhashed
subpacket.
The user distributes his key (other users, servers, ...ect).
Software A also allows the user to change this at a later date without
creating a new signature.
The user distributes this "updated" key.
How should the receiving software treat this "updated" data?
-- Ignore the "new" data
-- Accept the "new" data in place of the old data
-- Notify the receiver that there is "new" data and let him decide
-- ....?
--
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William H. Geiger III http://www.openpgp.net
Geiger Consulting
Data Security & Cryptology Consulting
Programming, Networking, Analysis
PGP for OS/2: http://www.openpgp.net/pgp.html
E-Secure: http://www.openpgp.net/esecure.html
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