Research On Key Technology Of SIP-Based VoIP Network Security

With the development and popularization of Internet technology,VoIP based on IP technology has a very good prospect of further development,with its advantages of low cost,small footprints.But VoIP also faces serious security threats because of IP network vulnerability. If these problems can not be solved,it Is bound to affect the further development of VoIP.As the main protocol of VoIP,Security of SIP has been questioned.Therefore,the paper focuses on key technology of SIP-based VoIP network protection,hoping to provide effective protection strategies.First of all,the paper introduces VoIP and SIP protocol,including the composition and function of SIP,the data format of SIP message,the basic call process of SIP.After studying these,there is a analysis of several common security threats in a SIP network which undermine confidentiality and authenticity of the message severely.Security defense strategy is proposed to against the threats,like key security mechanisms of TLS and IPsec,HTTP certification,S/MIME.The paper has a detailed study of DoS attack in SIP system because DoS attack has been the biggest security threat to VoIP currently by means of its simplicity and strong damage. Some mainstream attack methods are analyzed and verified in laboratory simulation environment.Then the paper suggests attention should paid to intermediary and the attacked party in defense.Finally,on the basis of earlier studies, the paper designs a SIP-based VoIP network protection framework.This part consists of basic ideas and steps of system designation, logical structure of the system and internal business processes.Several technology modules are involved in this framework,for instance,load dynamic equilibrium of network processor,SIP signaling,speech stream rendition,real-time detection and blocking of malicious content.