论文标题
EHAP-ORAM：有效的硬件辅助ORAM系统，用于非易失性内存
EHAP-ORAM: Efficient Hardware-Assisted Persistent ORAM System for Non-volatile Memory
论文作者
论文摘要
Oblevious RAM（ORAM）是可证明的安全原始性，可防止内存总线上的访问模式泄漏。它用作受信任的片组件和不信任的外部存储系统之间的中间层，以将原始内存访问模式调节为无法区分的内存序列。通过随机重建数据块并访问冗余块，Oram可防止访问模式通过混淆。尽管有很多事先的工作重点是改善Oram在常规的基于DRAM的内存系统上的性能，但是当存储技术转移到使用非挥发性内存（NVM）时，关于如何有效地支持Oram的崩溃一致性的新挑战。 在这项工作中，我们提出了EHAP-ORAM，该EHAP-ORAM研究如何使用基于NVM的内存系统坚持Oram构建。我们首先分析了持续的Oram系统的设计要求，并讨论了数据和Oram Metadata的崩溃一致性和原子性的必要性。接下来，我们讨论了持续的Oram系统设计中的一些挑战，并针对这些挑战提出了一些解决方案。然后，我们提出了经过修改的片上ORAM控制器体系结构。基于Oram Controller On-Chip的改进的硬件体系结构，我们提出了不同的持久性协议，以确保Oram System的碰撞一致性，并满足POSMAP中的元数据在信任/不信任的Off-Chip中持续到NVM时是安全的。提出的体系结构和持久性协议步骤最小化了在写回过程中的开销和泄漏。最后，我们将持久性的Oram与无碰撞一致性支持的系统进行了比较，表明在非恢复和递归案例中，EHAP-ORAM仅会产生3.36％和3.65％的性能开销。结果表明，EHAP-ORAM可以支持有效的碰撞一致性，并以最小的性能和硬件开销。
Oblivious RAM (ORAM) is a provable secure primitive to prevent access pattern leakage on the memory bus. It serves as the intermediate layer between the trusted on-chip components and the untrusted external memory systems to modulate the original memory access patterns into indistinguishable memory sequences. By randomly remapping the data blocks and accessing redundant blocks, ORAM prevents access pattern leakage through obfuscation. While there is much prior work focusing on improving ORAM's performance on the conventional DRAM-based memory system, when the memory technology shifts to use non-volatile memory (NVM), new challenges come up as to how to efficiently support crash consistency for ORAM. In this work, we propose EHAP-ORAM, which studies how to persist ORAM construction with an NVM-based memory system. We first analyze the design requirements for a persistent ORAM system and discuss the need to preserve crash consistency and atomicity for both data and ORAM metadata. Next, we discuss some of the challenges in the design of a persistent ORAM system and propose some solutions to those challenges. Then, we propose the modified on-chip ORAM controller architecture. Based on the improved hardware architecture of the ORAM controller on-chip, we propose different persistency protocols to ensure the crash consistency of the ORAM system and satisfy that the metadata in PosMap is safe when it is persisted to NVM in trusted/untrusted off-chip. The proposed architecture and persistency protocol steps minimize the overhead and leakage during the write-back process. Finally, we compared our persistent ORAM with the system without crash consistency support, show that in non-recursive and recursive cases, EHAP-ORAM only incurs 3.36% and 3.65% performance overhead. The results show that the EHAP-ORAM can support efficient crash consistency with minimal performance and hardware overhead.
