Design And Implementation Of An Open SSL-based Secure File Transfer System

Recently, more and more enterprises confidential data is transmitted via the Internet. However, it is very easy to be stolen and illegally used if the data is transmitted in clear text and information security need to be improved urgently. The traditional File Transfer Protocol has a weak ability to keep data safe, but the SSL provides a new method to solve the problems of the information security.After the requirements analysis of the project, an Open SSL-Based secure file transfer system is designed and implemented. Firstly, the research on SSL protocol is studied. On the basis of a deep understanding of the SSL protocol's principles, handshake process, symmetric and asymmetric encryption algorithms, certificate mechanism, a method using Open SSL library for the files' secure transmission is designed. Then research on concurrency server technology is done, and an algorithm is designed to solve the problem of the server concurrent processing, using the thread pool concurrency server technology and I/O multiplexing. Secondly, we do research on multi-thread transmission and broken transfer resume technology. After a detailed comparative analysis the methods, a suitable method for the system is designed. Finally, research on the user-defined file transfer protocol is done. Through the analysis of the client and server communication, a custom application transport protocol is designed that not only meets the needs of the system but also improves the file transfer efficiently.Finally, the function test and performance test are performed on the system. It turns out to be that the system achieves the desired effects and behaves smoothly, and has a great practical application value.