Anonymous veto network
In cryptography, the anonymous veto network (or AV-net) is a multi-party secure computation protocol to compute the boolean-OR function. It presents an efficient solution to the Dining cryptographers problem.
All participants agree on a group with a generator of prime order in which the discrete logarithm problem is hard. For example, a Schnorr group can be used. For a group of participants, the protocol executes in two rounds.
Round 1: each participant selects a random value and publishes the ephemeral public key together with a zero-knowledge proof for the proof of the exponent . A detailed description of a method for such proofs is found in the article Fiat-Shamir heuristic.
After this round, each participant computes:
Round 2: each participant publishes and a zero-knowledge proof for the proof of the exponent . Here, the participants chose if they want to send a "0" bit (no veto), or a random value if they want to send a "1" bit (veto).
After round 2, each participant computes . If no one vetoed, each will obtain . On the other hand, if one or more participants vetoed, each will have .
The protocol design
The protocol is designed by combining random public keys in such a structured way to achieve a vanishing effect. In this case, . For example, if there are three participants, then . A similar idea, though in a non-public-key context, can be traced back to David Chaum's original solution to the Dining cryptographers problem.
- F. Hao, P. Zieliński. A 2-round anonymous veto protocol. Proceedings of the 14th International Workshop on Security Protocols, 2006.
- David Chaum. The Dining Cryptographers Problem: Unconditional Sender and Recipient Untraceability Journal of Cryptology, vol. 1, No, 1, pp. 65-75, 1988