The durability of data stored in persistent memory (PM) exposes data to potentially data leakage attacks. Recent research has identified the requirements for crash recoverable secure PM, but do not consider recent trends of the persistency domain extending on-chip to include cache hierarchies. In this paper, we explore this design space and identify performance and energy optimization opportunities.We propose secure persistent buffers (SecPB), a battery-backed persistent structure that moves the point of secure data persistency from the memory controller closer to the core. We revisit the fundamentals of how data in PM is secured and show how various subsets of security metadata can be generated lazily while still guaranteeing crash recoverability and integrity verification. We analyze the metadata dependency chain required in securing PM and expose optimization opportunities that allow for SecPB to reduce performance overheads by up to 32.8×, with average performance overheads as low as 1.3% observed for reasonable battery capacities.

Due to its durability, the security of persistent memory (PM) needs to be ensured. Recent works have identified the requirements for correctly architecting secure PM to achieve crash recoverability. A key performance bottleneck, however, lies in the integrity tree update, which needs to be consistent with the memory persistency model and incurs a very high performance overhead. In this paper, we aim to drastically reduce this performance overhead.

Emerging non-volatile main memory (NVMM) is rapidly being integrated into computer systems. However, NVMM is vulnerable to potential data remanence and replay attacks. Memory encryption and integrity verification have been introduced to protect against such data integrity attacks. However, they are not compatible with a growing use of NVMM for providing crash recoverable persistent memory. Recent works on secure NVMM pointed out the need for data and its metadata, including the counter, the message authentication code (MAC), and the Bonsai Merkle Tree (BMT) to be persisted atomically. However, memory persistency models have been overlooked for secure NVMM, which is essential for crash recoverability.In this work, we analyze the invariants that need to be ensured in order to support crash recovery for secure NVMM. We highlight that by not adhering to these invariants, prior research has substantially under-estimated the cost of BMT persistence. We propose several optimization techniques to reduce the overhead of atomically persisting updates to BMTs. The optimizations proposed explore the use of pipelining, out-of-order updates, and update coalescing while conforming to strict or epoch persistency models, respectively. We evaluate our work and show that our proposed optimizations significantly reduce the performance overhead of secure crash-recoverable NVMM from 720% to just 20%.