一个公平的多方的不可否认协议

公平的不可否认协议解决了电子商务中信息传输的互相否认问题，使通信各方处于平等的位置。协议对各方都是公平的。该协议是基于组加密方法的，由可靠的第三方产生不可否认证据，数据交互次数少，高效实用。

A FAIR MULTI-PARTY NON-REPUDIATION PROTOCOL

Non-repudiation is one of the most important premises to achieve electronic commerce while fairness is what people have been chasing during electronic transaction. Fair non-repudiation protocols resolve the question of non-repudiation during the course of transferring information in electronic commerce and make all communicating sides in equal positions. That is to say, the protocols are fair for all sides. In the present paper, a fair multi-party non-repudiation protocol based on a group encryption scheme is introduced. The flow of the protocol and its analysis are given in the paper. In the protocol, every side can not have advantages over other sides, because the advantages can result in great loss of other sides. The method that how to solve the dissension with this protocol is also given in the present paper. A trusted third party is used to generate non-repudiation evidence. With this method the number of exchanged messages is small. So this protocol can achieve non-repudiation service in an efficient and practical way.