Provably secure one-round certificateless authenticated group key agreement protocol for secure communications

A novel one-round authenticated group key agreement (CL-AGKA) protocol is devised in this paper on certificateless public key cryptography. Our CL-AGKA protocol abolished the certificate management burden existing in certificate authority-based public key cryptography and the private-key escrow problem occurring in identity-based cryptography. Our CL-AGKA protocol is designed to establish an authenticated group session key between a group participants by ensuring that the session key is not revealed to any outsiders. The proposed CL-AGKA protocol designed a security model in the computational model, called the random oracle model. It is formally examined that our CL-AGKA protocol achieved the strong authenticated key exchange security and thus provably secured in the random oracle model. The security of the designed protocol is achieved against the intractability assumptions of the computational Diffie---Hellman problem and bilinear Diffie---Hellman problem. In addition, the proposed CL-AGKA protocol offered low message exchange cost and computational cost against the related group key agreement protocols.