The System Of Electronic Seal Based On Digital Signature And Digital Watermark

The thesis researches the problem about how to develp the electronic seal system.According to the problem,the thesis constructs the development environment of the Visual C++6.0 and Visual Basic6.0 and puts forword the solution scheme about how to develop the electronic seal system,which solves the above mentioned problem to some extent.Currently, the way of realization electronic seal quite effective can use the digital signature technology and the digital watermark technology. So the technology of cryptography, information hidden, etc. are all theoretical foundations of realizing the electronic seal. Meanwhile, CA system and digital certificate are theoretical foundations that electronic seal system is involved. Firstly, the thesis analyzes and compares the production and technology of the current some kinds of the electronic seal system.Then, the thesis puts forword a solution scheme of the electronic seal syetem, through inserting multi-layerd numeral watermark and changing the position of the documents digital signature to enchance system security. According to the differences of seal information sensitivity, the system uses the direct memory and the encryption memory way, which inserts the information to the seal bitmap and serves as the anti-false sign of the seal.The documents digital signature is no longer attached to the documents behind, but it is inserted by the digital watermark way to the seal picture. It realizes the one-to-one relation of seal and file. Thus illegal users unable to fabricate seal and tamper file. Finally, the thesis implements the primary functions of seal execution, seal management and document transmission.The practical development manifests that adopting the solution scheme can develop the better electronic seal system and provide the new ideas and technique methods on the research of electronic seal system.