Abstract: Integrity measurement is an important technology to meet the requirements of Trusted Computing.According to various kinds of elements which influence the integrity of operating system，a trust degree evaluation model is constructed based on the computing formulas of direct trust degree，indirect trust degree and overall trust degree.With fuzzy set theory，this model quantifies the integrity measurement values between [0，1].Using membership function，the operating system’s trust degree can be divided into four trust levels，but not the false or true judgement method in current integrity measurement model.This method can supply more precise integrity state of computing platform for remote verifier and improve the usability of compute system.The simulation results show that the model gives more objective integrity information of the operating system.

Key words: trust degree, integrity, fuzzy set

摘要： 完整性度量是可信计算得以实现的一项重要技术。根据影响操作系统完整性的内核模块、二进制可执行文件等因素，通过定义直接信任度、间接信任度和综合信任度等计算公式构建了一个操作系统的完整性信任度评估模型，该模型利用模糊集合理论将完整性度量化为[0，1]之间的具体数值，并根据隶属函数将操作系统的信任度划分为四个信任等级。该模型改变了原有完整性度量中一致执行、不一致停止的二值状态，为远程验证者提供较为精确的操作系统完整性度量值，提高了系统的可用性。仿真实验结果表明该模型较客观地提供了操作系统的完整性信息。

关键词: 信任度, 完整性, 模糊集合