Password-Based Group Authenticated Key Exchange Protocol: From 3-Party to Group

Password-based authenticated group key exchange (denoted by PGKE) provides n parties who hold a common human-memorable password for secure group communication. In this paper, applying the cryptographic technique to a password-authenticated 2-party key establishment protocol without random oracle assumption, a password-authenticated group key exchange under the help of a trusted server with CDH assumption is proposed. Comparing with other existing protocols, this protocol does not require any Server's public key and encryption of simple password (low-entropy).