关键词: 隐通道, 语法信息流分析, 访问控制, 保密性安全策略

Abstract: The traditional syntactic information flow analysis is based on the lattice model such that the method can not be used to analyze the security of systems implementing the security policy not satisfying transitivity. This paper proposes a new information flow analysis approach. First, information flow semantics is attached to each statement of a program language. Then a graph structure called information flow temporal relation is defined to describe the temporal relation of information flow occurring, and a method of constructing the graph structure is presented. Fi-nally, based on the graph structure a covert information flow identification method is developed. In addition, ac-cording to the concurrency feature of concurrent programs, a method for reducing the information flow temporal relation is proposed. With the help of the method, it is sufficient to consider the special interleave order between concurrent processes instead of all interleave orders.

Key words: covert channel, syntactic information flow analysis, access control, confidentiality security policy