| This dissertation gives an overview on status in WLAN Intrusion Detection Technology in the world, and introduces the conceptions, protocols, security techniques and risks of the WLAN. Based on the research of the intrusion detection theory technology and method, a close study is made on the WLAN Intrusion Detection technology.A architecture of the DWIDS(Distributed WLAN Intrusion Detection System) are presented.The dissertation lucubrates the components and their functions in the DWIDS and presents corresponding technology and introduces the topology of the DWIDS in the WLAN. At last, the dissertation emphasizes the study on two key techniques of the DWIDS.l.A close study is made on the pattern matching technology of the WIDS.After a study is made on the components,structure and characteristics of WLAN Intrusion Rules, this dissertation gives particular rules' description of some typical attacks, and introduces the pattern matching of the rules.Then,a study is made on the pattern matching arithmetic.The dissertation presents a new pattern matching arithmetic-QBM arithmetic.The new arithmetic uses the most long prefix to match.and uses a shift table to calculate shift value in the matching of postfix.The dissertation proves that the QBM arithmetic is superior to BM arithmetic on theory and in practice.2. After the discussion of the static Markoff chain model,the dissertation establishs a normal set called Stat Model, which can be used to calculate a support probability of the experimental data sequence.The probability is a standard which is used to determine the existence of the abnormal behavior.Then an abnomal detection method based on the static Markoff chain model is discussed, and a detection arithmetic is brought forward, the results of experiment is given. |
