Hi Phill,
Hallam-Baker, Phillip wrote:
The sequence of events hypothesized is:
1) Sender determines that the existing algorithm is deprecated
2) In response to (1) sender prepares to support an additional signature
algorithm
3) In order to support (2) sender publishes an additional key record for the
new algorithm
4) Mallet starts sending bogus messages with forged signatures purporting to be
under the new key
5) Receivers that have not yet upgraded to support the new algorithm are unable
to determine that the messages with forged signatures are inconsistent with the
signer's policy.
I think that that is clear. However, what do you say to the fact that
anyone can produce a message with a bad signature that does adhere to
such a policy? (By looking up the policy or copying a real example.)
Given that problem I really don't see what the receiver can confidently
do with such a message that differs from handling a totally unsigned
message. Can you provide some examples?
Thanks,
S.
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