基于一个新型的消息恢复的数字签名方案，提出一个安全高效且节省网络资源的公平不可否认协议。它具备的基本性质有：公平性、不可否认性、可终止性、实用性、高效性、机密性等。另外，协议依赖的第三方是离线工作的，它只在意外情况下才介入，且不必完全可信。因为通信实体之间交易的信息对它保密。还有，它的失误能被检测到，故该协议可实现网上交易的最优化。

Based on a digital signature with message recovery, we present a new fair non-repudiation protocol with features of security, efficiency and economical use of net resources. It has the properties of fairness，non-repudiation，secrecy，termination， etc。The third party of the protocol intervenes into the exchange in case of problems，and it need not be completely trusted，because the message which is exchanged between the parties is secret to the third party。In addition， its fault can be identified。So the protocol can optimize exchanges via Internet。