Secure Scattered Memory: Rethinking Secure Enclave Memory with Secret Sharing

Abstract

The rise of cloud computing demands secure memory systems that ensure data confidentiality, integrity, and freshness against replay attacks. Existing schemes such as AES-XTS, AES-GCM, and AES-CTR each trade performance for security, with only AES-CTR plus Message Authentication Codes (MAC) and Merkle Trees (MT) providing full protection - at the cost of substantial counter and MT overhead. This paper introduces Secure Scattered Memory (SSM), a novel scheme that replaces counter-based encryption with polynomial-based secret sharing. Each data block is encoded into multiple cryptographically independent shares distributed across memory, inherently preventing information leakage while ensuring integrity and freshness through mathematical reconstruction properties. Implemented and synthesized in a 28 nm commercial PDK, SSM occupies 0.27 mm^2 and consumes 284.53 mW. Experiments show only 10% and 8% performance overhead over AES-XTS and AES-GCM, respectively, while outperforming Morphable Counter (MICRO 2018) by up to 40%, achieving 12% better performance than EMCC/RMCC (MICRO 2022), and exceeding COSMOS (MICRO 2025) by 3%.