Improving identity privacy and authentication in SIP transactions

Session Initiation Protocol (SIP) has gained more acceptability as the number of Voice Over Internet Protocol (VoIP) applications grows significantly. However, SIP itself lacks user privacy, necessary security properties, and has poor performance due to chosen cryptographic operations. A number of security techniques were proposed to address user privacy issues, but they still have limitations in terms of security and performance. In this paper, SIPPEN, a SIP Privacy Enhancement with Nicknames, is introduced. SIPPEN can preserve privacy of SIP users while they communicate. Moreover, a new authentication technique between a user agent and a proxy server is introduced. The results given from our analysis show that the proposed protocol not only has higher security level, but it also has better performance comparing to existing techniques.