i-NVMM: A Secure Non-Volatile Main Memory System with Incremental Encryption

摘要

Emerging technologies for building non-volatile main mem ory (NVMM) systems suffer from a security vulnerability where information lingers on long after the system is pow ered down, enabling an attacker with physical access to the system to extract sensitive information off the memory. The goal of this study is to find a solution for such a security vul nerability. We introduce i-NVMM, a data privacy protection scheme for NVMM, where the main memory is encrypted incrementally, i.e. different data in the main memory is en crypted at different times depending on whether the data is predicted to still be useful to the processor. The motiva tion behind incremental encryption is the observation that the working set of an application is much smaller than its resident set. By identifying the working set and encrypt ing remaining part of the resident set, i-NVMM can keep the majority of the main memory encrypted at all times without penalizing performance by much. Our experiments demonstrate promising results. i-NVMM keeps 78% of the main memory encrypted across SPEC2006 benchmarks, yet only incurs 3.7% execution time overhead, and has a negligible impact on the write endurance of NVMM, all achieved with a relatively simple hardware support in the memory module.