Abstract
IP multimedia subsystem (IMS) is an emerging platform for provisioning multimedia services in 4G/5G networks. IMS authentication is an important procedure which grants legitimate users access to these services. The main problem is periodic re-authentication of users that results in significant signaling traffic overhead due to complete execution of hectic procedure. Moreover, SIP overlooks users' privacy where public and private identities are not protected. This paper presents a Secure and Efficient Authentication Protocol (SEAP) which creates a secure channel through the deployment of a key management center for transmitting user identities. Elliptic curve cryptography is used for key generation. Once a user completes authentication, SEAP grants a valid ticket for a particular time, which can be used for subsequent re-authentications until it expires. We introduce a header in SIP to hold the ticket. We employ protocol composition logic for formal modeling and verification of SEAP. The performance of SEAP is validated through FOKUS which is an IMS testbed. The results demonstrate the performance supremacy of SEAP compared to contemporary schemes.