Password-only authenticated key establishment protocol without public key cryptography

A scenario in which a user and a server can authenticate each other and generate a strong session key through a symmetric cipher by their shared weak (low-entropy) password in an insecure channel is considered. Until now, designing a secure protocol in this scenario has been an open problem due to the offline dictionary attack. A protocol to resolve this problem is proposed. The idea is to ensure that people must participate to verify each guessed password in the offline dictionary attack. Therefore, this attack cannot succeed in a reasonable time for the proposed protocol.