Mixed Password Simulation System Research And Implementation,

With the fast development and wide application of the computer networkingtechnology, information sharing is realized in the world. People can send or get theinformation what they need conveniently. But because of the networking openness,networking protocol imperfection and operation systematic loophole, networkinginformation can be gotten, replaced, deleted and modified by the unauthorized users.Severe menaces are taken to networking system. The development and application ofcryptography technology are paid more attention in recent years. The security ofinformation transmission is enhanced with cryptography technology encryptingnetworking information.Cryptography is the core of the information security. Modern cryptography dividesinto the public key system and the symmetric key system. In the actual application, acombined encryption system is general used, that is, the symmetric encryptionalgorithm is used to encrypt the information that will be transmitted, and the public keyencryption algorithm is used to transfer the symmetric key. At the same time, a digitalsignature based on the public key encryption algorithm is used to verify the integrityand authenticity of the information.This thesis introduces the related concepts about network security and cipher,briefly introduces many kinds of encrypt algorithms, expatiating RSA public-keyalgorithm and the program flow of DES algorithm, which are the typical representativesof symmetric cryptosystem and public cryptosystem respectively, and then introducesthe key exchange technology. Based on this, this thesis puts forward the randomized keyexchange system based on RSA, which used DES key as session key to handle the plaintext and encrypt text, and uses RSA key pair to encrypt/decrypt DES key in order tokeep security. Finally, different safety methods such as RSA digital signature, DES dataencryption and hybrid cipher system of DES and RSA are designed using VC++6.0, andthe 2400-bitted long RSA key can be created in comparatively short time. Thesealgorithm has been testified to work in high efficiency and this system has been testifyto have high security. The hybrid cipher system can be used widely in the e-commerce,the secure instant messaging, the secure e-mail,etc.