Date Added: Nov 2012
Session Initiation Protocol (SIP) is a powerful signaling protocol that increasingly used for administrating Voice over IP (VoIP) phone calls. In recent years, Session Initiation Protocol (SIP) is more and more popular. However, there are many security problems in the Session Initiation Protocol. SIP authentication mechanism is based on HTTP Digest authentication, which this scheme Is insecure; such as off-line password guessing attacks and impersonate other parties and etc. So, researches proposed different schemes to secure the SIP authentication. In the year 2012, Tang et al. proposed a SIP authentication protocol using Elliptic Curve Cryptography (ECC), but their scheme is insecure against off-line password guessing and Registration attacks.