Abstract: Context information is one of the key factors in pervasive access control systems,which exerts a decisive influence on authorization and access control on subjects. Permissions of the subjects,threshold intensity of the resources and security policies of the system should be automatically adjusted as the changes of the context information in pervasive computing environment, without thorough consideration by current access control models. In order to describe the active influence of fuzzy context information on pervasive access control (permissions of the subjects, the threshold intensity and the security policies of the system)，based on the traditional ECA rules and the intcrvalfuzzy set thcory,a fuzzy ECA rule scheme was designed, and an active access control method was proposed based on the proposed fuzzy ECA rule scheme. By applying the new access control method, the pervasive access control can be self-adjusted in the pervasroc cnmronmcnts.

Key words: Access control, Active access control, Interval-valued fuzzy reasoning, Fuzzy ECA rule, Pervasive computing