Abstract: The hot path of small software is scarce and short. Usually, two programs have similar hot paths when they result in same function. If the birthmarks are extracted from small software, the credibility of birthmark is weak. This paper presents a new approach to software birthmarking based on expanded hot path. Using impact analysis, the codes which are closely related to the hot path are merged into hot paths. This approach expands hot paths in the DAG graph which is the output of SEQUITUR algorithm. By preserving the call order among expanded hot paths, the birthmark is formed. The experiment shows that, the resilience of this birthmark and WPP（Whole Program Path） birthmark are identical. The credibility overtops the WPP when applied in small program.

Key words: software birthmarking, hot path, Whole Program Path（WPP）, impact analysis

摘要： 小型程序能提取的频繁执行路径数量少，路径相对较短，程序功能相近时路径相似度高，不适于构造高可信性软件胎记。提出频繁执行路径扩展技术，通过影响分析方法，在SEQUITUR算法输出的DAG图上，查找频繁执行路径上每一节点的影响节点，把这些节点加入到路径后，形成扩展频繁执行路径。实验表明，保持扩展频繁执行路径调用关系形成的软件胎记，其可靠性不低于WPP胎记，当程序较小时，可信性高于WPP胎记。

关键词: 软件胎记, 频繁执行路径, 全局程序路径, 影响分析