Abstract: The highly development of information technology has brought new challenges to information security.Because of the lack of time and space constraints，traditional RBAC model cann’t meet the new requirements of information system.On the basis of RBAC，the definition of spatio-temporal domain is introduced，each element of the model is constrained with time and space，and the spatio-temporal role based access control model（TSRBAC） is proposed.In this paper，TSRBAC is described formally，spatio-temporal role hierarchy and spatio- temporal separation of duty are defined.The spatio-temporal access control algorithm has also been given.

Key words: role-based access control, spatio-temporal domain, spatio-temporal constraint, spatio-temporal separation of duty

摘要： 信息技术的高度发展对信息安全提出了新的挑战，经典的基于角色的访问控制（RBAC）中缺乏对时间和空间的约束，使RBAC模型不能适应信息系统新的安全需求。在RBAC的基础上，引入了时空域的定义，对模型中各要素进行了时间和空间约束，提出了具有时空约束的角色访问控制模型（TSRBAC）。形式化地描述了TSRBAC，并定义了时空角色继承和时空职责分离，给出了时空访问控制算法。

关键词: 角色访问控制, 时空域, 时空约束, 时空职责分离