面向属性约束的自动信任协商模型

An Attribute-Constraints-Oriented Automated Trust Negotiation Model

针对已有自动信任协商系统策略语言粒度粗糙、不能生成所有信任序列且缺乏评估与择优机制等问题,提出一种面向属性约束的自动信任协商模型———ACATN.其具有如下特点:利用属性约束细化策略语言粒度,不仅有效地保护了敏感服务和证书,而且提高了系统的灵活性;使用全局访问控制策略终止不会成功的协商请求,从而提高协商效率;采用信任序列搜索树描述信任序列的生成过程,基于此树的宽度、深度优先搜索算法在快速生成一个信任序列的同时,能够生成所有的信任序列;通过属性证书披露代价和通信开销评估信任序列,以便于系统选择最优信任序列.结合具体实例对ACATN模型的使用进行了说明.

The existing automated trust negotiation systems suffer from the following drawbacks： the policy languages are coarse-grained, the negotiation strategy cannot generate all trust sequences, and the mechanism to evaluate and select： trust sequences is absent. To address the above problems, an attribute-constraint-oriented automated trust negotiation （ACATN） model is proposed. The policy language is refined by using attribute constraint, which can not only effectively protect sensitive services and certificates, but also enhance its flexibility. The global access control policy is used to terminate impossible negotiation in advance so that the negotiation effi- ciency can be improved. The process of generating trust sequence is described by trust sequence searches tree. Based on the tree, the breadth-first and depth-first searches generate not only a trust sequence quickly, but also all trust sequences. Trust sequences are evaluated via disclosure cost and communication overhead so that the optimal one can be selected. ACATN is illustrated using a typical example.