Simple Three Party Key Exchange Protocols via Twin Diffie-Hellman Problem
In the secure communication areas authenticated key exchange protocol is one of the most important cryptographic mechanism. In 1992, Bellovin and Merrit proposed the first Encrypted Key Exchange (EKE) family of key exchange protocols, which allow people to use easy to remember passwords without being threatened by dictionary attacks. In the EKE protocol, two communication parties securely share a password in advance, and authentication is achieved after these two parties obtain a common ephemeral session key. However, as the passwords are of low entropy, password based authenticated key exchange protocols are vulnerable to password guessing attacks.