LAUSR

The session initiation protocol (SIP) is a signaling protocol which is used to controlling communication in the Internet. It is also used for initiating, terminating and maintaining the sessions. A strong authentication scheme plays a pivotal role in safeguarding communications over the Internet. In order to ensure the secure communication, several authentication schemes have been proposed for SIP in the literature. Recently, Lu et al. proposed an authentication scheme for SIP-based communications and proved that their scheme can resist various network attacks. In this paper, we show that their scheme is susceptible to the user and server impersonation attacks. Also, their scheme fails to achieve user anonymity and mutual authentication. Hence, there is a need to propose a secure ECC-based authentication scheme with user anonymity for SIP to overcome the shortcomings of Lu et al.’s scheme. Security analysis shows that the proposed scheme is able to fix the flaws found in Lu et al.’s scheme. In addition to informal security discussions, we give formal security analysis of the proposed scheme under the generic group model of cryptography. Performance analysis also shows that the proposed scheme is suitable for SIP based communication.