Because of the fact that user’s identities are not enough to prove whether he is trusted or not

this paper presents a method to establish trust relationship automatically based on user’s attributes.Credential which includes some encrypted attributes is exchanged firstly between strangers.And then two parties exchange secret key iteratively based on own access control policies to show sensitive attributes.It appears better performance such as small-storage-space

small-calculate-task and strong-resist-attack than that of traditional trust establishment methods.