带离线半可信第三方的多方交换协议

A fair multi-party exchange protocol with theoff-line trusted third party

对已有的各种公平交换协议及不可否认协议进行了比较分析.利用公开可验证秘密共享及群加密方案,提出一个新的基于离线半可信第三方的多方公平交换协议.离线第三方只在意外情况下才介入协议,实现了网上交易的最优化;离线第三方不必完全可信,因其只能解密半个密钥分量;保证了交换数据的机密性和交换拓扑的保密性(包括第三方);参与方可因意外事故退出协议而无损公平,使交易更加灵活且符合实际.

The difference between the fair exchange protocols and the non-repudiation protocols is proposed. Based on the publicly verifiable secret sharing scheme and group encryption scheme, a new multi-party fair exchagne protocol with an off-line semi-Trusted Third Party(off-STTP) is presented. The off-STTP who need not be completely trusted intervenes into the exchange in case of trouble. That the off-STTP can only decipher a sub-secret key makes sure the confidentiality of exchange data and the true fairness of the barter. The participants can barter with others at their will and the exchange topology is unknown to others including the off-STTP.