COVERT: Counter OVErflow ReducTion for Efficient Encryption of Non-Volatile Memories

摘要

Security vulnerabilities arising from data persistence in emerging non-volatile memories (NVMs) necessitate memory encryption to ensure data security. Whereas counter mode encryption (CME) is a stop-gap practical approach to address this concern, it suffers from frequent memory re-encryption (system freeze) for small-sized counters and poor system performance for large-sized counters. CME thus imposes heavy overheads on memory, system performance, and system availability in practice. We propose Counter OVErflow ReducTion (COVERT), a CME-based memory encryption solution that performs on-demand memory allocation to reduce the memory encryption frequency of fast growing counters, while also retaining the area/performance benefits of small-sized counters. Our full-system simulations of a phase change memory (PCM) architecture across SPEC CPU2006 benchmarks show that for equivalent overhead and no impact to performance, COVERT simultaneously reduces the full memory re-encryption frequency from 6 minutes to 25 hours and doubles memory lifetime in comparison to state-of-the-art CME techniques.