A general compiler for password-authenticated group key exchange protocol

Password-authenticated group key exchange protocols allow that a group of participants who share a human-memorable (short) password can obtain a common session key in a secure way over public networks. In this paper, we design a compiler, which transforms any basic group key exchange protocol (which is only resistant against benign adversaries) into a password-authenticated group key exchange protocol. We prove that the new protocol outputted by the compiler is secure in the random-oracle and ideal-cipher models if the underlying group key exchange protocol is secure. Our compiler is practical since it only needs four more additional rounds of communications, which means that the new protocol still holds constant-round property if the original one is a constant-round scheme.