Identity-Based Cryptography (IBC) was originally introduced by A. Shamir in 1984 in a signature scheme. IBC was first applied in the encryption and decryption of messages in the Boneh and Franklin model presented in 2001, which forms the basis of our design. In this model, the system has to undergo private key refreshment procedure as part of the key management, which requires multiple control packets that increase the communication overhead. In this paper, we propose Enhanced Identity-Base Cryptography (EIBC), an efficient key management mechanism that minimizes control packets communications. Furthermore, we elucidate how EIBC can be employed in multicast group key managements. We present analysis to show that EIBC simultaneously achieves a high level of system security while handling system key management in an efficiently manner. EIBC can be utilized and implemented in various platforms, e.g., in our efficient authentication and key management schemes for Smart Grid networks.