Abstract: Role-Based Access Control（RBAC） has been generally accepted as one of the most promising access control policies，and it has become a hot research topic in information security area.However，traditional RBAC model is not completely fit for the access control in pervasive computing environment.In this paper，trust management technology is introduced on the basis of traditional access control model and the trust-based access control model in pervasive computing （TBAC） is proposed.It evaluates the trust degree of subjects according to interval-valued fuzzy theory and the access control policy is made by the trust level of the subjects who request to access.The subjects with higher trust degree and reliability are classified into higher trust level，and then the role-assign procedure assigns the trust level to a corresponding role.So it meets the requirements of pervasive computing environment better.

Key words: pervasive computing, access control, trust degree, role, fuzzy synthetic judgment method, fuzzy clustering

摘要： 基于角色的访问控制模型（RBAC）被普遍认为是当前最具有发展潜力的访问控制策略，已成为信息安全等领域研究的热点之一。然而传统的RBAC模型不能完全适合普适计算环境下的访问控制。在传统RBAC模型的基础上引入信任管理技术，提出了基于信任的模糊访问控制模型（TBAC）。通过区间值模糊理论实现对主体信任度进行评估，依据请求访问主体的信任度所属信任域设置访问控制策略，对于信任值和可靠性高的主体可以划分到比较高的信任域中，访问控制中的角色指派则可以将某一个信任域指派到角色集的一个角色上，从而实现由主体到角色的指派，更加适合普适计算环境下的访问控制要求。

关键词: 普适计算, 访问控制, 信任度, 角色, 模糊综合评判法, 模糊聚类