Password Based Anonymous Authentication with Private Information Retrieval

This paper focuses on authentication with three types of entities: a user who sends an authentication request, an service provider who receives and verifies the request, and a database who supplies the authentication-server with information for verifying the request. This paper presents novel authentication protocols that satisfy the following important properties: (1) secure against replay attacks and (2) the database cannot identify which user is authenticating First, we show a protocol with a single database which satisfies Properties (2). Second, we show a protocol which satisfies Properties (1) and (2). A key idea of our authentication protocols is to use private information retrieval (PIR) [Chor et al. J. ACM, 1998].