A Multi-user Oblivious RAM for Outsourced Data

Outsourcing data to remote storage servers has become more and more popular, but the related security and privacy con-cerns have also been raised. To protect the pattern in which a user accesses the outsourced data, various oblivious RAM (ORAM) systems have been proposed. However, existing ORAM designs assume a single user or a group of mutually-trusted users to access a remote storage, which makes them inapplicable to many practical scenarios where multiple users share data but may not trust each other. Even if the data-sharing users do trust each other, such systems are vulner-able to the compromise of even a single user. To study the feasibility and costs for overcoming the limitation of existing ORAMs in multi-user scenarios, this paper proposes a new type of ORAM system calledMulti-user ORAM (M-ORAM)