中文摘要：

信任链发现是信任管理的主要内容．由于在分布式环境中凭证分布于各个节点，并且对于相同或相似的请求现有的信任链发现算法需要大量重复的通信和计算开销进行凭证的搜集和验证，极大地影响了信任关系验证的效率．在分布式信任链发现算法的基础上，结合网络中的信任关系相对稳定的特点，基于缓存的原理实现了一个可扩展的层次式monitor机制用于保存信任链发现过程中产生的中间结果，并且采用订阅机制保证其有效性，从而有效避免对相似的信任关系验证而产生的重复通信和计算开销．实验表明，采用该机制的分布式信任链发现算法在信任关系相对稳定的情形下具有较高的效率．

英文摘要：

Trust chain discovery is the main focus of the trust management system. In distributed systems, the credentials are stored on the nodes which spread around the network. There are too many redundancies among these credentials. Current trust chain discovery mechanisms spend much time on collecting credentials from many different nodes, and waste many computing resources to verifying the redundant credentials. Based on the current distributed trust chain discovery algorithms, this paper proposes an extensible cascaded monitor mechanism which makes use of the stability of the trust relationships and the similarity of the credentials to boost trust chain discovery process. The cascaded monitors can save the intermediate knowledge generated during the trust chain discovery process, and can be used in succession. It reduces the time of the communication and the cost of the computation for collecting and verifying the credentials markedly. The experiment shows that the algorithms with the cascaded monitor mechanism are more efficient than the others, especially, for the situation where are many stable trust relationships.