Authorization is a part of trust management

the existing systems have some faults as follows: one is "one time authorization

effective for ever"

the other is authorization depth is not controlled effectively. To address the problems

this paper proposes a multi-level authorization management model in distributed system. This model uses a way based on the trustworthiness to authorize and inspect every entity regularly. To the entities that does not conform the condition

they will be took out. Moreover

the correspondence among the entities is controlled by the authorization root

strengthen the depth control.