Design Of VOIP Chaotic Secure Telephone Based On SIP Protocol

With the popularization of network bandwidth and improvement of voice transmission,VOIP is favored by people because of its cheap cost and high quality voice.The openness of the Internet has also brought great challenges and threats to information safety,so we should pay more attention to the safety of information.Due to the chaotic sequence generated by the chaotic system are sensitive to the initial value,so the encryption key is suitable for the encryption system.In this dissertation,by improved Henon mapping,period window is reduced and key space is extended,in this way the chaotic parameter interval is increased.In order to prevent the use of a single chaotic sequence as a key security problem,a dynamic IP packet encryption scheme based on VOIP is designed.Based on the SIP protocol,this dissertation designs the VOIP client based on Android platform,and the security of the voice signal is encrypted to ensure the security of the two Android clients.The experimental results show that the dynamic packet encryption and decryption system can encrypt the speech signal and has high security performance.The main research work of this dissertation is as follows:(1)Firstly,the chaos theory and chaotic system are deeply studied.Based on the original Henon mapping equation,the improved chaotic system is used to increase the chaotic parameter interval.The random performance of the sequence and encryption algorithm are the key points in chaotic encryption system,so the performance of chaotic sequences is very important to the security of the system.The NIST performance test is carried out to validate the random sequence of improved Henon map.NIST test results show that the chaotic sequence has good random performance and can be used in the VOIP encryption system.(2)The development history and research status of VOIP are briefly intro duced.On this foundation,this dissertation analyses the architecture of SIP prot ocol such as the principle of the protocol,signaling mechanism,message transf er mechanism and registration process,and also introduce the structure and und erlying implementation details of the SIP protocol.(3)The dynamic IP packet encryption algorithm is used to encrypt the digital voice signals.The dynamic allocation mechanism can ensure the security of the system.The connection-less UDP protocol is used to transmit voice signals in order to solve the problem that receiver can not correctly decrypt signals due to the network problem.(4)The design of the system based on the C/S architecture and SIP client based on the Android platform which is designed by JAVA language.In order to analysis the establishment and connection process of SIP messages,WireShark capture tool is used to examine the information in network transmission process.In order to test the VOIP security phone based on SIP protocol,the transmission rate,packet loss rate,call delay and other technical indicators are analyzed.Finally,because the key in this system is dynamically allocated,the randomness of the chaotic sequence is enhanced,and the security of voice transmission is guaranteed.The test results show that the system has good security performance.