One-Server Private Information Retrieval Scheme combined with Mutual Authentication by ElGamal Signature

In e-commerce, the protection of users´ privacy from a server was not considered feasible until the private information retrieval (PIR) problem was stated and solved. A PIR scheme allows a user to retrieve a data item from an online database while hiding the identity of the item from a database server. In this paper, a new PIR scheme combined with authentication by ElGamal signature for protecting the privacy of users is proposed. Using only one server (combined with secure coprocessor) and including the mutual authentication process in the proposed scheme, it is more secure and more practical in the real e-commerce environment compared with previous PIR solutions