The Design And Realization Of Ims-based Voip High-speed Media Security Gateway

With the rapid development of internet technology in the direction of digital, integrated, The Internet has deeply influenced the People’s Daily life and work. Using IP networks to provide voice, fax, video, data and other multimedia real-time services has become a trend and also promotes application popular. However, due to IP packets are easy to be attacked by hackers, there are lots of security risk in current IP networks, such as critical information loss or intercepted.The objective of this paper is to design and implement a high-speed Vo IP Security Gateway. A Vo IP encryption system is composed of this gateway, secure terminals and manage devices,which were completed by the entire project team. RTP(Real-Time transport protocol) packets are encrypted by this gateway in this system and the Vo IP voice communication is safe also for users.The Vo IP communication system and some protocols used in this system were firstly described and analyzed in this paper.After that, we analyse several kinds of popular technologies,which were used in signaling control and Data encryption fields. RTP(real-time communication protocol) packets were encrypted, using AES algorithm(Advanced Encryption Standard). Based on the above researches, the design and realization of Vo IP Security Gateway. was achieved. The design tasks are composed of hardware design and software design.Driver development, data encapsulation and key agreement scheme are designed in software design.The hardware section includes the selection of main chip, principle block diagram of the design, the construction of peripheral circuit and the implementation of AES algorithm based on FPGA. This paper introduces in detail the design of the hardware circuit and the Verilog codings Of key modules. Software design does not belong to the contents of this thesis research, Therefore, this paper did not elaborate on the specific design process of software.Finally, we deploy an open source SIP server in our test network, voice encryption and encryption performance of security gateway are evaluated. Furthermore, the security of Vo IP communications is verified through packet capture analysis.