3 ms·

Thanks for your reply. Pertaining your last point, I've actually already added some scope creep to the OP (see the second paragraph of the question section, per

Thanks for your reply. Pertaining your last point, I've actually already added some scope creep to the OP (see the second paragraph of the question section, pertaining expiration, etc.).

kmowery 12y ago
That's still fairly straightforward; change the message A signs to "I trust Gamma. Nonce: whatever. Valid Until: DateTime". B should then 1) check the signature and 2) check the datetime (in that order).