In order to effectively master protocol interactive behavior, a method to automatically build protocol interactive process based on message sequence chart was proposed. Firstly, according to the characteristics of the protocol interactive process, the dependency graph was defined to represent the partial order of events in message sequence, and the network flows were converted to dependency graphs. Secondly, the basic message sequences were used to describe protocol interactive behavior fragments, and the basic message sequences were mined by defining event maximum suffix. Finally, the maximum dependency graphs that were found out were connected and merged to build a message sequence chart. The experimental results show that the proposed method has a high accuracy and the built message sequence chart can visually represent the protocol interactive process.

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.