关键词: 安全标记, BLP模型, 可信度, 客体关联, 数据聚类

Abstract: The paper analyzes the disadvantage of BLP model in the application of multi-level secure network，on the basis of which a network enclave boundary BLP model is put forward for adapting to multi-level network.It imposes protection domain relational restriction to control the connection of multi-level network enclave boundary.It uses the trust degree of network subject to solve access control between subject and object on special situation，and strengthens flexibility and adaptability of access control based on secure label.At the same time，the relation of objects is studied deeply to analyze the problem about loss of secret for the association of independent objects and aggregation of similar objects and an access control with objects relational restriction is put forward to strengthen restriction of confidentiality in multi-level network.

Key words: secure label, BLP model, trust degree, object association, data aggregation