中文摘要：

给出了鉴别协议猜测攻击的串空间模型．扩充了攻击者串和密码运算类型，重新定义了理想概念，并证明了相关定理．扩展的诚实理想分析模型不仅继承了原理论的有关性质，而且适应猜测攻击的分析．以GLNS协议为例说明了如何利用串空间理论有效地进行协议的形式化分析．

英文摘要：

The strand space model to analyze guessing attack on the authenticated protocol based on passwords was proposed. The penetrator＇s strands were extended through adding guessing traces and the types of cryptographical operation. A new notion of ideal was defined and relative theorems were therefore modified and proved. The extended honest ideal model not only inherits its original characters, but also is adaptive for the analysis of guessing attack. The GLNS protocol was utilized to illuminate how to analyze a protocol formally and effectively by the use of this extended strand spaces.