Efficient Fair Secure Two-Party Computation

Yao first introduced a constant-round protocol for secure two-party computation (2PC) withstanding semi-honest adversaries by using a tool called "garbled circuit". Later, many protocols based on garbled circuit approach have been presented, most of which discussed malicious adversaries and efficiency about 2PC. However, there only have a few protocols dealing with the fundamental property of fairness for Yao\´s garbled circuit approach, in which one involved a trusted third party and the others are very expensive. In the paper, we propose\´ an efficient Yao\´s garbled circuit protocol for fair secure 2PC based on ElGamal encryption, Pedersen commitment, Cachin et al.\´s verifiable oblivious transfer and Ou-Ruan et al.\´s gradual release homomorphic timed commitment. The protocol achieves two advantages: it doesn\´t need the third party and it is more efficient than other fair secure Yao\´s protocols.