A Dynamic and Recoverable BMT Scheme for Secure Non-Volatile Memory

Abstract

Data security is a key issue that non-volatile memory (NVM) system designers must consider. However, this is challenging because implementing security mechanisms such as bonsai merkle tree (BMT) in NVM needs to ensure crash recovery due to the non-volatile property of NVM. Existing schemes fail to efficiently guarantee the atomic BMT root update and instant system recovery required for BMT crash recovery, resulting in large write traffic and performance overhead. In this paper, we propose DR-TREE, a dynamic and recoverable BMT scheme for secure NVM, which reduces the update overhead of BMT root and achieves fast crash recovery with low write traffic. DR-TREE dynamically builds BMT and adjusts the updated BMT levels according to memory write requests, thus reducing unnecessary update overhead of BMT root. Next, based on the locality of memory write requests, DR-TREE merges repeated BMT updates, further decreasing the update overhead of BMT root. Moreover, DR-TREE achieves fast crash recovery with extremely low write traffic by delaying the partial recovery process. Experiments show that compared to the state-of-the-art design, DR-TREE improves the performance by 44.6%, decreases write traffic by 78.2% and achieves the system recovery in 5ms.