There is no reliable trust system in Internet nowdays.It attracts more and more attentions how to express and manage trust relations in a distributed and disordered network system.

• 目前在因特网中没有可靠的信任体系,如何在一个分布的、混乱的因特网环境中有效地表达和管理信任关系已成为一个研究热点。