International Association
for Cryptologic Research

Many online services adopt a password-based user authentication system because of its usability. However, several problems have been pointed out on it, and one of the well-known problems is that a user forgets his/her password and cannot login the services. To solve this problem, most online services support a mechanism with which a user can reset a password. In this paper, we consider a provable security treatment for a password reset protocol. We formalize a model and security definitions, propose a generic construction based on a pseudorandom function and public key encryption. In addition, we implement a prototype of our protocol to evaluate its efficiency.