What technique is used in the Off-The-Record protocol to implement authentication and message validation? And what is the difference between this technique and Multi-Designated Verifier Signatures?
As far as I understand it, the OTR protocol uses digital signatures and HMAC for authentication for one-to-one communication. Each communication will publish the MAC key of the previous round of communication with the message, so that everyone can get this key to create message and calculate at MAC value,achieve deniability, but I think this will not be responsible.
MDVS can be used for group communication,and the designated receiver knows the identity of the sender,and the receiver can take responsibility for problems.
As for mpOTR, I'm trying to understand: I think in communication, multi-party OTR protocol users involved in communication do not know each other's identity, which is not accountable.
These are my guesses, I do not know whether they are correct...