Authentication of Signaling in VoIP Applications

Session Initiation Protocol known as SIP is currently being preferred to H. 323 protocol due to its simple architecture. In Traditional SIP, security mechanisms are inadequate for assuring the identity of the end user based on cryptography. This is vulnerable in the sense that a third person, an impersonator, may easily duplicate one of the users engaged in the session. This can pose serious threats as it affects secrecy of the user. In order to reduce the threat posed by an eavesdropper, an authentication scheme is required. This paper proposes a scheme for authenticating the end users identities with the outbound proxy server in that domain with the help of the registrar server. The authentication scheme is based on end users public key infrastructure (PKI) certificate and strong one way hash function. The proposed scheme is implemented using JAVA and tested for its validity in a LAN environment. The delay overhead in providing authentication in the proposed scheme is found to be within the allowable limit as per IETF standard.