关键词: 角色，完整级，完整性控制，安全模型，操作系统

Abstract: Integrity is one of the security objectives of operating system. This paper analysed the integrity protection policies of security operating system, and elaborated user responsibility and process reliability arc important factors in determining the integrity level of the users,the processes and the files in operating system. Then we proposed an integrity control model with detailed description of its integrity axiom, model elements, system states, system configurations and state transition rules. The model employs roles to simplify user integrity management. The correctness of given model was proven. The application case and implementation method were given at the end of the paper.

Key words: Role, Integrity level, Integrity control, Security model, Operating system