公平交换协议与传统的安全协议有所不同，导致公平交换协议的设计原则与传统的安全协议设计原则有所区别，因此，必须根据公平交换协议的特点重新考虑一些要素。本文根据公平交换协议的特点，另外给出了4条针对公平交换协议的设计原则，并以攻击为实例来说明这些原则的重要性。这些原则与传统的安全协议的设计原则结合起来，使得公平交换协议从设计的开始就能够考虑各种可能会出现的错误与漏洞，从而大大提高协议设计的质量。

Fair exchange protocols are different from classical security protocols, which resulted in the differences in design principles between them. Therefore, when designing fair exchange protocol, the designer needs to reconsider some other factors. Based on the characteristics of fair exchange protocols, in this paper, the authors put forward four new design principles. In order to illuminate the importance of these principles, the authors give some attack examples. With these principles, the designer can consider the various possible vulnerabilities and errors at the beginning of fair exchange protocol design. Therefore, the quality of protocol design is improved greatly.