Identity based authenticated group key agreement protocol

An important and popular trend in modem computing is to convert traditional centralized services into distributed services spread across multiple systems and networks. One-way function trees can be used to extend two-party Key Agreement protocols to n-party protocols. Tree-based Group Diffie-Hellman [17] is one such protocol. This paper proposes the first Identity based Group Key Agreement protocol by extending the Identity based two-party Authenticated Key Agreement protocol [13] using the One-way function trees. A new function called the transformation function is defined, which is required in generating keys at any level from a lower level key in the key tree. The new protocol provides complete forward and backward secrecy. Authentication is implicit in this protocol, whereas it has to be explicitly dealt with in other Key Agreement protocols. ID-AGKA protocol is more advantageous for systems without a deployed PKI.