Research On Technique And Algorithm Of Digital Signature

This paper starts with basic concept of cryptography, and then, researches the digital signature techniques and related algorithms. Safer efficient and practical encryption algorithms are proposed, based on the classic algorithms. Then, the paper studies the digital signature technique based on PKI. In the end, a set of visual digital signature system is designed, accomplished and applied in enterprise.First of all, the paper introduces basic concepts, principles and the domestic and abroad development state in this research area. Then, it studies mathematical models of the classic algorithms, and introduces MD5, DES, RSA, ECC...etc in detail. And then, it compares their advantages and their disadvantages.According to the comparison and analysis of classic digital signature algorithms, the paper proposes a digital signature solution which not only takes their advantages, but also avoids their disadvantages: the mixed encryption based on DES&RSA and the mixed encryption based on DES&ECC. The former solves the contradiction between secret key's management and processing speed of encrypt algorithm (It is hard to manange secret key in DES, and the procssing speed is slow in RSA), and forms a set of signature solution which can be performed conveniently, circulated efficiently, and of high security. The later depends on the theoritical advantages of ECC algorithm. Besides the advantages list above, at the same time, it advances greatly on the aspects of processing speed, algorithm's complexity and security etc. It is one of the most developed and mature signature solutions.At last, the paper studies the digital signature technique based on PKI(Public Key Infrastructure), proposes a safer PKI solution which is suitable to enterprise. In the solution, the secrete key and certificate are managed by CA, not by users themselves, which makes secrete key and certificate transparent to users. And then, we design and implement a visual digital signature system which can be applied in enterprises. This system integrates the digital signature technique into the office software. Users can sign their documents like word documents, excel documents, visio documents and other types of documents in office software safer and more reliably with this system. And also, this system embeds signature into document by using the XML technique and AcitiveX technique rather than encloses it with document. Furthermore, this system realizes two signature modes. One is mode signature, and the other is modeless signature, which makes it more practical.The system has been used in DaQing GoldBridge Information Technology Company, and the result is good.