zkPAKE: A Simple Augmented PAKE Protocol (short paper)

NOTE: Cryptanalized by Michel Abdalla through private communication, and publicly in https://eprint.iacr.org/2017/961.
Human memory is notoriously unreliable in memorizing long secrets, such as large cryptographic keys. Password-based Authenticated Key Exchange (PAKE) protocols securely establish a cryptographic key based only on the knowledge of a much shorter password. In this work, an augmented PAKE pro- tocol is designed and proposed for secure banking applications, requiring the server to store only the image of the password under a one-way function. The protocol is more efficient than alternatives because it requires fewer public key operations or a lower communication overhead.