中文摘要：

公平交换协议是电子商务的关键技术．本文根据公平交换协议和串空间的特点，定义了丛最大（极大）结点、良序丛的概念．依据协议的消息驱动特征，建立了串空间结点标号的递归公平交换协议分析方法．分析了ZG协议并发现一个很多其它分析没有发现的缺陷，分析结果既肯定了本文方法的可用性又给出了一个具体的应用。

英文摘要：

Fair exchange protocols are the key technology in e-commerce. In term of the characteristics of both fair exchange protocols and strand spaces, this paper defines two new notions： bundle＇s maximum node and well-ordered bundle. According to the idea of message drive of fair exchange protocols, a recursive analysis method is constructed here. A ZG fair non-repudiation protocol is analyzed and found a flaw which wasn＇t detected by some other analysis. This analysis both verifies the feasibility and illustrates a concrete application of our method.