基于尺度的时空RBAC模型

A Role-Based Access Control Model Based on Space,Time and Scale

空间技术的广泛应用,使得空间数据的安全日益重要.空间数据库的访问控制已经成为目前国内外研究的热点问题.现有的空间数据访问控制模型主要分为2大类:一类是对RBAC模型扩展,加入空间位置的判断,提供基于位置的服务,但这类模型缺乏对空间数据自身特性的分析;另一类是基于矢量数据或栅格数据提出的自主访问控制模型,这类模型分析了空间数据的特征,如几何表示、拓扑关系等,但是缺乏一个通用的模型.在传统RBAC模型中扩展了空间位置、时间和尺度等基本数据元素,提出基于尺度的时空RBAC模型(STS-RBAC).通过在角色激活中加入位置和时间的约束条件,增加了空间信息使用的安全性;针对矢量数据和栅格数据定义尺度的概念,增强了访问控制策略的表达能力;同时定义操作集、尺度和空间对象间的关系,使得相关授权信息具有更为简单的表达形式和自动推导特性,减少了重复存储和访问次数,提高了权限判定效率.

With the development of space technology, people pay more and more attention to the use of space data. Space data cannot be accessed without any restriction. So the access control models of space data are becoming more and more important. This is also a hot spot in current research in the world. Presented in this paper is an STS RBAC model, which is an improvement of traditional RBAC model. STS-RBAC model is based on the spatial database operations and it includes the attributes of space, time and scale. It can also be used in vector data and raster data. This model can manage the problems of multi-scale spatial objects as well. Scale, as is all known, is a basic element in the security of spatial data such as time and space. STS-RBAC model focuses on the special character of spatial data, and introduces role hierarchies based on the constraints of position and time, which guarantees the reliability in spatial database access. STS-RBAC model also defines the transmissibility and partial order in permissions, which makes it possible that authorizations can be inferred from others. This decreases the time and space when spatial database is accessed. With the help of STS- RBAC model, it is possible to access spatial data more efficiently and securely.