In this paper, we propose an efficient identity-based password authenticated key exchange (IBPAKE) protocol using identitybased KEM/DEM. In IBPAKE, a client conducts authentication based on a human-memorable password and a server’s identity. A distinctive feature of IBPAKE protocols, compared to the well-known EKE-like PAKE protocols, is that an adversary who even acquired a user’s password cannot impersonate a server to further investigate user’s sensitive information. We first construct the new IBPAKE protocol using the Boneh- Franklin identity-based encryption (IBE) scheme, and then generalize the protocol by presenting a generic method to yield an efficient IBPAKE protocol from identity-based KEM/DEM. Our fine-grained approach has concrete advantages in terms of performance. First, unnecessary parameters can be removed easily. This allows a straightforward improvement on computational cost and communication bandwidth. Our protocol gives better performance, compared to previously known IBPAKE protocols.