IRO: Integrity–Reliability enhanced Ring ORAM

Abstract

Memory security and reliability are two major design concerns in cloud computing systems. State-of-the-art memory security–reliability co-designs (e.g., Synergy) have achieved a good balance in performance, security, and reliability. However, these works merely rely on encryption to ensure data confidentiality, which cannot avoid information leakage from memory access patterns. Ring ORAM is an attractive confidentiality protection protocol to hide memory access patterns to the untrusted system. Unfortunately, it lacks memory integrity and reliability support, and it is incompatible with the security–reliability co-designs. A forced combination of Ring ORAM with the general integrity and reliability schemes would result in severe performance and storage overhead. In this paper, we propose IRO, an Integrity–Reliability enhanced Ring ORAM design. First, we analyze the inefficiency of general integrity protection methods and propose RIT, an integrity verification scheme for Ring ORAM that does not have extra integrity metadata access overhead. Then, we analyze the memory waste in Ring ORAM and propose Secure Replication, the reliability scheme that provides channel-level memory error resilience with very little storage overhead for replicas. We conduct cycle-accurate simulations to analyze the efficiency of our design. The results show that IRO increases 7.56% execution time of the baseline Ring ORAM in the case of limited MAC computation units. With enough computation resources, IRO can reduce the execution time of the baseline by 2.11%.