A lightweight scheme for securely and reliably locating SIP users

Voice over Internet protocol (VOIP) is a fast growing technology believed to be the future replacement for traditional public switched telephone network (PSTN) networks. VOIP offers many benefits over PSTW, but there are still lots of issues when it comes to service reliability and security. One of the problems faced is how to locate communicating parties on the Internet in a secure and reliable manner. The security mechanisms included in RFC 3261 session initiation protocol (SIP) are either weak or expensive to deploy. In this paper, we propose a light weight scheme that can protect the integrity of SIP contact addresses. This scheme also achieves high availability of SIP services through replication. End user public key distributed in this scheme can also be used for end-to-end user authentication and media session key exchange.