A Novel Formal Theory for Security Protocol Analysis of Denial of Service Based on Extended Strand Space Model

Denial of Service Distributed Denial of Service （DOS） attack, especially （DDoS） attack, is one of the greatest threats to Internet. Much research has been done for it by now, however, it is always concentrated in the behaviors of the network and can not deal with the problem exactly. In this paper, we start from the security of the protocol, then we propose a novel theory for security protocol analysis of Denial of Service in order to deal with the DoS attack. We first introduce the conception of weighted graph to extend the strand space model, then we extend the penetrator model and define the goal of anti-DoS attack through the conception of the DoS-stop protocol, finally we propose two kinds of DoS test model and erect the novel formal theory for security protocol analysis of Denial of Service. Our new formal theory is applied in two example protocols. It is proved that the Internet key exchange （IKE） easily suffers from the DoS attacks, and the efficient DoS- resistant secure key exchange protocol （JFK） is resistant against DoS attack for the server, respectively.

Towards the Idealization Procedure of BAN-Like Logics

We demonstrate the flaws of Mao's method, which is an augmentation ofprotocol idealization in BAN-like logics, and then offer some new idealization rules based on Mao'smethod. Furthermore, we give some theoretical analysis of our rules using the strand spaceformalism, and show the soundness of our idealization rules under strand spaces Some examples onusing the new rules to analyze security protocols are also concerned. Our idealization method ismore effective than Mao's method towards many protocol instances, and is supported by a formalmodel.

Formal analysis of robust email protocol based on authentication tests

Based on the authentication tests and the strand space model, the robust email protocol with perfect forward secrecy is formally analyzed, and the security shortcomings of the protocol is pointed out. Meanwhile, the man-in-the-middle attack to the protocol is given, where the attacker forges the messages in the receiving phase to cheat the two communication parties and makes them share the wrong session keys with him. Therefore, the protocol is not ensured to provide perfect forward secrecy. In order to overcome the above security shortcomings, an advanced email protocol is proposed, where the corresponding signatures in the receiving phase of the protocol are added to overcome the man-in-the-middle attack and ensure to provide perfect forward secrecy. Finally, the proposed advanced email protocol is formally analyzed with the authentication tests and the strand space model, and it is proved to be secure in authentication of the email sender, the recipient and the server. Therefore, the proposed advanced email protocol can really provide perfect forward secrecy.

Research and improvement on the limitation of authentication test

This paper elaborated on the limitation of authentication test theorem, illustrated the fundamental cause of that limitation through examples, then enhanced authentication test to solve this problem, and also proved the soundness of that improvement with formal method. The enhanced theory can deal with protocols with test component as proper subterm of other regular node＇ s component under certain conditions, and extend the application scope of authentication test. With enhanced authentication test, the automatic protocol verification tools will be more efficient and convenient.

Novel analysis and improvement of Yahalom protocol

The modified version of Yahalom protocol improved by Burrows, Abradi, and Needham （BAN） still has security drawbacks. This study analyzed such flaws in a detailed way from the point of strand spaces, which is a novel method of analyzing protoeol＇s security. First, a mathematical model of BAN-Yahalom protocol is constructed. Second, penetrators＇ abilities are restricted with a rigorous and formalized definition. Moreover, to increase the security of this protocol against potential attackers in practice, a further improvement is made to the protocol. Future application of this re-improved protocol is also discussed.

Analysis of security protocols based on challenge-response

Security protocol is specified as the procedure of challenge-response, which uses applied cryptography to confirm the existence of other principals and fulfill some data negotiation such as session keys. Most of the existing analysis methods, which either adopt theorem proving techniques such as state exploration or logic reasoning techniques such as authentication logic, face the conflicts between analysis power and operability. To solve the problem, a new efficient method is proposed that provides SSM semantics-based definition of secrecy and authentication goals and applies authentication logic as fundamental analysis techniques, in which secrecy analysis is split into two parts： Explicit-lnformaUon-Leakage and Implicit-Information-Leakage, and correspondence analysis is concluded as the analysis of the existence relationship of Strands and the agreement of Strand pa- rameters. This new method owns both the power of the Strand Space Model and concision of authentication logic.