More and more cryptographic protocols have been used to achieve various security requirements of distributed systems in the open network environment. However cryptographic protocols are very difficult to design and an...More and more cryptographic protocols have been used to achieve various security requirements of distributed systems in the open network environment. However cryptographic protocols are very difficult to design and analyze due to the complexity of the cryptographic protocol execution, and a large number of problems are unsolved that range from the theory framework to the concrete analysis technique. In this paper, we build a new algebra called cryptographic protocol algebra (CPA) for describing the message operations with many cryptographic primitives, and proposed a new algebra model for cryptographic protocols based on the CPA. In the model, expanding processes of the participants knowledge on the protocol runs are characterized with some algebraic notions such as subalgebra, free generator and polynomial algebra, and attack processes are modeled with a new notion similar to that of the exact sequence used in homological algebra. Then we develope a mathematical approach to the cryptographic protocol security analysis. By using algebraic techniques, we have shown that for those cryptographic protocols with some symmetric properties, the execution space generated by an arbitrary number of participants may boil down to a smaller space generated by several honest participants and attackers. Furthermore we discuss the composability problem of cryptographic protocols and give a sufficient condition under which the protocol composed of two correct cryptographic protocols is still correct, and we finally offer a counterexample to show that the statement may not be true when the condition is not met.展开更多
探讨了形式化分析在设计密码认证协议中的作用;基于Needham Schroeder共享密钥协议和Ot way Rees协议,提出了新的认证协议,并用BAN逻辑对它进行形式分析,发现了潜在的攻击方法,指出形式分析可以辅助发现协议的设计缺陷;并讨论了这种分...探讨了形式化分析在设计密码认证协议中的作用;基于Needham Schroeder共享密钥协议和Ot way Rees协议,提出了新的认证协议,并用BAN逻辑对它进行形式分析,发现了潜在的攻击方法,指出形式分析可以辅助发现协议的设计缺陷;并讨论了这种分析的局限性以及可能的改进方向.展开更多
文摘More and more cryptographic protocols have been used to achieve various security requirements of distributed systems in the open network environment. However cryptographic protocols are very difficult to design and analyze due to the complexity of the cryptographic protocol execution, and a large number of problems are unsolved that range from the theory framework to the concrete analysis technique. In this paper, we build a new algebra called cryptographic protocol algebra (CPA) for describing the message operations with many cryptographic primitives, and proposed a new algebra model for cryptographic protocols based on the CPA. In the model, expanding processes of the participants knowledge on the protocol runs are characterized with some algebraic notions such as subalgebra, free generator and polynomial algebra, and attack processes are modeled with a new notion similar to that of the exact sequence used in homological algebra. Then we develope a mathematical approach to the cryptographic protocol security analysis. By using algebraic techniques, we have shown that for those cryptographic protocols with some symmetric properties, the execution space generated by an arbitrary number of participants may boil down to a smaller space generated by several honest participants and attackers. Furthermore we discuss the composability problem of cryptographic protocols and give a sufficient condition under which the protocol composed of two correct cryptographic protocols is still correct, and we finally offer a counterexample to show that the statement may not be true when the condition is not met.
