Based On Sha-1 Algorithm For E-mail Filtering System

Recently, In order to win the maximum interest, some companies and personssend a large numbers of commercial advertisements and bad information toconsumers using E-mail unobtain the content of the user. These actions bring to theappearance of the spam that has abominable impact to the society. Aiming at thisstatement, this paper design and achieve an effective system of filtering to damp theflooding of spam after synthetically analyzing all kinds of the methods of spam filterand comparing the advantage and disadvantage of these methods.The paper analyzes the acturality of the filter field, and discusses the majormethods of the filter system and the general methods that the spam sender used. Itcan be said that nowadays most of the methods are based on the text checking such asthe method based on the NN, the method based on the Bayes and so on. Thesemethods have distinct flaws. Aim at these flaws and integrate the merits, the paperdesign and achieve a fire new system.At first, this paper focus on the basic knowledge of mail system because only wehave deeply familiar with the mechanism of mail system, can we roundly grasp theimplement of the mail filter technology. The paper also has analyzed the mail headstructure in that it is the key in the process of the mail filter. Much importantinformation is picked up from the head structure. In order to apply the SHA-1arithmetic to the system of mail filter and consequently improve the efficiency of themail filter, the paper briefly analyze the theory and mechanism of the encryptarithmetic and compare the several major arithmetic.Secondly, synthetizing all kinds of mail filters'characteristic, the paper outlinethe frame of the mail filter based on the SHA-1 arithmetic, and discuss some keypoints such as the choice of the filter point, the choice of the hash arithmetic, the flowof the filter and so on. Aiming at the characteristic of the spam and rationally utilizethe predominance of the hash arithmetic, the paper combine many other methods offilter so as to make the system effective.After the general design, the paper partitions the system to several modules andmakes detailed design and implement. The major modules include head structureanalyse module, text analyse module, hash module, storage module and so on.In the end, we carry a huge number of tests in order to validate the effect of thefilter. The result shows that the system can work in gear and reach the anticipative...