COVERT: Counter Overflow Reduction for Efficient Encryption of NonVolatile Memories

Shivam Swamia and Kartik Mohanramb
Department of Electrical and Computer Engineering, University of Pittsburgh, PA.


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.

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