无须可信第三方的防滥用公平交易协议

Abuse-free fair exchange protocol without TTP

基于改进的完美并发签名,提出了一个无须可信第三方的防滥用公平交易协议,该协议避免了既有方案中买方滥用交易信息获得额外利益的缺陷。协议中,买方对订单、支付凭证、数字内容进行模糊签名;卖方确认买方的消息内容后,对数字内容的哈希结果和买方的订单、支付凭证一起进行模糊签名,买方提供使签名公开可验证的keystone后,卖方提供数字内容的解密密钥。买、卖双方的签名数据中包含了数字内容、支付凭证、订单信息,使得买卖双方的模糊签名与交易信息形成惟一的绑定关系,避免任何一方对签名数据和交易信息的滥用。该协议无须可信第三方介入,解决了可信第三方不容易获得、第三方可能与某一方勾结以及可信第三方的性能瓶颈等问题,适合在P2P交易环境中应用。

Based on the improved perfect concurrent signature, this paper proposed an abuse-free fair exchange protocol without trusted third party. This protocol avoided the flaw, by which buyer could prove to others that he has done an artificial trade with the shop, existed in other fair exchange protocols based on perfect concurrent signature. In the proposed protocol, buyer and shop bound the order information, payment information, and digital content together in the ambiguity signature which could be verified pubhcly after the buyer released extra keystones. And the buyer could get the key from the shop to decrypt the cipher of the digital content he wanted after he released keystones. The keystones bound the ambiguity signature, deal information of the buyer and shop together to avoid any one of the signer abuse these information. This protocol could be used in P2P network in which it＇ s hard to find a trusted third party. Also using this protocol could avoid the risk that third party cooperating with one party to cheat others and avoid the performance bottleneck caused by third party.