Abstract: The techniques of verifiable secret sharing and verifiable encryption are used in the construction of two party fair exchange protocols. The novelty of the construction lies in the introduction of the distributed semi-trusted third party. Compared to the previous fair exchange protocols with a single semi-trusted third party, the newly constructed fair exchange protocol can further guarantee the security and fairness of the transaction due to the existence of the distributed semi-trusted third party

Key words: Verifiable secret sharing; Verifiable encryption; Fair exchange; Semi-trusted third party

摘要： 运用可验证秘密分享和可验证加密技术设计了一个安全的双方公平交换协议。该协议引入了分布式的半可信第三方，与已有的具有单一半可信第三方的公平交换协议相比，分布式半可信第三方的存在使新协议的安全性和公平性得到了更好的保证。

关键词: 可验证秘密分享；可验证加密；公平交换；半可信第三方