Cipher And EDBSmail Realization Research In Network Data Security

In the information times, with the unprecedented development of computer network, various application of information transfer on network platform would need more security and secrecy. In the network, normally, the data can be divided into static data and dynamic data, static data is stored in workstation, dynamic data is transferred on the network. To counter these data types, at present, there are two security methods: fire-wall combined with password, human body's characteristics distinguish and other techniques are often used to safeguard the static data, and data encryption and description are often used to safeguard dynamic data . As a practical network, the safety of dynamic data especially will be given prominence to.This paper mainly deals with the security protect of dynamic data, researches related cryptograph mechanism and system, and try to combine design with application depending on different researches, which is concerned with EDBSMail running on Internet/Intranet. Thereby, it could satisfy the need of different network security communication.In this paper, depending on research block encryption algorithms, the left and right sides unsymmetrical encryption will be proposed. That is, when a plain text to be encrypted, different encryption algorithms should be combined first, and then, the plain text would be processed by the combined algorithm. This method will not only waste no time, but also can strengthen the ability of defencing attack notably. At the same time, the design method of nonlinear S-boxes is given out, the method allows to design different bit length of S-box, and thereby, the secret key length can be increased which would strengthen the ability defenced attack of encryption algorithm.In authentication algorithm research, a new nonlinear hash algorithm is taken up. It is different from MD-4. MD-5 and SHA, combined with S-box to make the security stronger.Otherwise, a secret protected algorithm and a block encryption algorithm based on hash function are taken up also. They are all of efficient parts of EDBSMail.In the end, through discussing and researching combine with various encryption algorithms, an electronic mail system based on encryption Data-Base is taken up, which is running on Internet and Intranet The main idea of designing is to take various encryption algorithms as a component of the Data-Base, and allow user to select any algorithm by it's need, meanwhile, the security level is considered. User can add new algorithm into the Data-Base by itself. As a very important characteristic, an interface to definite algorithm is offered by the algorithm DB. With the Data-Base created, it is possible that user can combine different algorithms into one algorithm.The COM (Component Object Model) is used in EDBSMail and middle size package reuse can be realized. Otherwise, other characteristics are also absorbed in EDBSMail, such as: created public key Data-Base with PKI and share secret to protect private key; created user agency with Winsock, set up daily files record which would be audited easily; applied digital signature in not deny and etc .