中文摘要：

在概率Applied Pi下对安全协议的匿名度进行研究：它在概率Applied Pi进程上定义了metric，以对进程间的相似进行度量；该定义被证明是有效的，因为当两个进程之间的metric为0时这两个进程弱互模拟；基于metric给出了匿名度的形式化定义。最后分析了密码学家就餐问题，用概率Applied Pi对其建模，计算匿名度。

英文摘要：

This paper studied the anonymity in the model of probabilistic Applied Pi （ PAPi ）. First, defined a metric on PAPi processes to measure the similarity between processes. This metric was then shown to be well-defined since it turns out to be 0 when two processes are weakly bisimilar. Upon metric, gave the formal definition of anonymity degree. Finally, as an illustrating example, analyzed the anonymity of probabilistic dining cryptographer problem （DCP） in framework.