Abstract: A novel multi-party key agreement protocol with password authentication for ad hoc network is proposed. The protocol is composed of system initialization, ID-based password evolvement algorithm, identity authentication algorithm and session keys generation algorithm. The protocol combines ID-based password evolvement with Waters signature to guarantee the validity of public key and the reliability of the node’s identity. The freshness and security of password are guaranteed by sharing password evolvement every time in node’s identity authentication and key agreement. The new protocol enjoys many secure properties such as against dictionary attack, against man-in-middle attack, against replay attack, key independence, forward security, backward security, etc. The analysis shows that the protocol is very suitable for ad hoc network.

Key words: ad hoc networks, key authentication, identity authentication, key agreement