Research And Design Of File Encryption System Based On USB Security Key

With the rapid development of the electronic information technology, the electronic file is used extensively. The security of the electronic information becomes focus in the field of information security. The secure storage of e-file is the precondition of ensuring information security, which is generally realized by encryption.Being the key technology of information security, encryption technology is getting more and more popular. The application of the encryption technology is no longer limited in the fields of military affairs, political affairs and foreign affairs. Its commercial values and social values have been fully affirmed. So, the further research on encryption technology is very important and valuable, and it has a wide prospect.USB Key is developed from technology of smart card.It combine with technology of cryptology,technology of smart card and technology of USB.It is new generational product of identity authentication.USB Key is more convenient and speedy than serial communications of smart card, so It will replace old authentication mode and widely use in PKI application field.In order to realize data encrypt, figure sign with identity USB security key, authentication of function carrying on systematic research in this paper. Based on analysis the foundation theory of security key system, in addition introduced infrastructure of security key, fundermental function and cryptosystem, and put forward a enpryption method based on USB security key. The method is combined of software and hardware application, software processes file encryption, thus hardware takes charge of key management and conversation key encryption. The special advantages of the symmetric algorithm and public-key algorithm are used to encrypt the important e-file. That is, the symmetric encryption algorithm used to encrypt the e-file, public-key algorithm is used to transfer the keys that have used. At the same time, Message-Digest algorithm is used to verify the intergrity and authenticity of the information. The system achieves high security, efficiency and expediency. At the same time, based on the characteristic of USB security key, system possesses high expansion.