Abstract: This paper introduces the theory of access control model based on role and task, and analyzes task and the shortage of above models. It puts forwards a new access control mode based on role and task to make access control more flexible. The formalized meaning, restriction and application in school grid are also presented.

Key words: RBAC, TBAC, Restriction

摘要： 介绍了基于角色的访问控制模型和基于任务的访问控制模型的原理。分析了以上两种模型存在的问题，为了使访问控制更灵活，提出了一种基于角色和任务的访问控制模型，并给出了模型的形式化定义、授权约束和在校园网格中的应用。

关键词: 基于角色的访问控制, 基于任务的访问控制, 约束