Efficient publicly verifiable 2PC over a blockchain with applications to financially-secure computations

Abstract

We present a new efficient two-party secure computation protocol which allows the honest party to catch dishonest behavior (if any) with a publicly-verifiable, non-repudiable proof without sacrificing the honest party's secret. Comparing to the best existing protocol of its kind, ours requires a substantially simpler judge algorithm and is able to process circuit evaluator's input-wires two orders of magnitude faster. Further, we propose an automated, decentralized judge implemented as a blockchain smart-contract. As a killer application of combining our two-party PVC protocol with our decentralized judge, we proposed the concept of financially-secure computation, which can be useful in many practical scenarios where it suffices to consider rational adversaries. We experimentally evaluated our prototype implementation, demonstrated the 2PC protocol is highly efficient and the judge is very affordable to protect users against rational attackers.