关键词: 文件分级保护, Bell-LaPadula (BLP)模型, 信息聚合, 可信主体, 完整性

Abstract: To solve the problems existing in BLP (Bell-LaPadula) model, such as information aggregation leakage, excessive privileges of trusted subject and the deficiency of integrity, with reference to the application requirement of hierarchical file protection, an information aggregation leakage proof model named IALP (Information Aggregation Leakage Proof) was proposed based on assignment partition. First of all, the cause of information aggregation leakage and the current research situation were discussed. Secondly, on the basis of assignments partition, the knowledgeable degree of subject and the information weight of object were quantized, and the relatively trusted subject was proposed. Security axioms and state transition rules were given. Finally, the theoretical proof, application examples and analysis indicate that IALP can control the knowable degree of the subject towards the object set with the aggregation leakage relation, and limits the privilege of trusted subject and enhances the integrity to some extent.

Key words: hierarchical file protection, Bell-LaPadula (BLP) model, information aggregation, trusted subject, integrity