Design And Implementation Of Electronic Seal System Based On Improved Algorithm Of MD5

E-government affair must through a lot of electronic documents and exchange, then its various functions was able to be really realized. Meanwhile, the electronic document must keep authoritative, believable and executive ability. So, we need an electronic seal system has the same authoritative, believable, safe as the real stamp system, in order that the electronic document in electronic government affair system has the same force adeffect and executive ability.The focus of the thesis is the research and analysis on related key Technologies of electronical seal system. These Technologies consist of cryptography, watermark technologe, PKI/CA, middleware technologe and so on. The.method of differential analysis on collision attacks against MD5 was analyzed. Based on the previous work, the thesis proposed a new improved algorithm of step function and message preprocessing on MD5. The results show that:the improved step function of MD5 can raise the resistibility of collision attack by preventing choosing a good differential path and limiting the use of message modification techniques.Finally, we accomplished the electronic seal system in District Government with the improved MD5 Algorithm step function and other key technology. The achieved specific features as follows:Electronic seal of the production, application, report the loss and cancellation features; the production of a digital certificate, application, report the loss and write-off and other functions. Stamp and verify the electronic document; the key technology of the system is digital signature technology, and we improved the security of electronic seal system by using the improved step function of MD5 in digital signature technology of the thesis.