No abstract

This paper develops system software in application layer based on Linux operating system. Linux operation system in this paper. Different transmission modes are adopted in different parts to improve the transmission efficiency in the network. The data capture encryption method is used for the file data, and the storage transmission method is used for the image data. It designs an identity authentication protocol and key exchange protocol based on digital certificate and digital sign technology, to avoid the sophistication and filch and improve the reliability of the identity authentication and the security of the key exchange. The common algorithms of symmetric encryption, asymmetric encryption and information digest are studied by using OpenSSL standard library function to realize data encryption module of the system.