Implementation Of The File Encryption And Decryption Wireless Transmission System Among Multiple Terminals

At present,terminals exchange information through Internet.But this way of exchanging information has serious limitations.Under the situations of unavailability of basic network infrastructures,terminals cannot interconnect to exchange information successfully through Internet.It is very necessary to depend on the wireless transmission protocol supported by terminals.However,the security mechanism implemented in the wireless transmission protocol is found loopholes.The way of encrypting or decrypting data at the application layer becomes the important method to improve safety.So the file transfer system is implemented by combining wireless transmission protocol and data encrypted or decrypted mechanism at the application layer.This way has become the research hotspot in the field of terminal interconnection transmission.In this thesis,it firstly analyzes the theory of the protocol of Wi-Fi Direct,the communication and security problems.Then it designs the detailed scheme foucused on the protocol of Wi-Fi Direct to set up file encryption and decryption wireless transmission system.The system scheme is focused on the Android mobile terminals.It implements terminals interconnection through Wi-Fi Direct and it solves the problem of point-to-point communication and the port conflicts during concurrent transmission;it implments the bridging communication among the group owner terminlas through access points;it implements mobile terminlas communication with PC(Personal Computers)terminals through FTP(File Transfer Protocol);it sets up backend servers(cloud terminals)through LAMP(Linux + Apache + MySQL+ PHP)to implement the file transfer and storage between cloud terminals and mobile terminals.The overall system finally implements the transmission bwtween mobile terminals and PC terminals,between cloud terminals and mobile terminals and among mobile terminals.The test shows that in the interconnection of mobile terminals,the file transfer success rate between intra-group and inter-group is at least 93% and 91% respectively;the speed of file transfer is at least 1.01MB/s and 1.03MB/s respectively;the speed of file encryption and decryption reaches at least 10.2MB/s and 8.37MB/s respectively.The system has greate research significance and practical application value for implementing stable and secure file transfer among terminals.