Toward Secure, Reliable, and Energy Efficient Phasechange Main Memory with MACE The emerging generation of cloud computing systems demand highperformance, energy efficiency, and dense, highbandwidth memory. An emerging concern is inmemory encryption to protect data in these environments. New memory technologies, such as phasechange memory (PCM), have been proposed to improve storage density and energy efficiency, with a near DRAM performance, while suffering from endurance challenges. Industry leaders like Intel and Microsoft have established AESXTS encryption as the de facto standard to provide the required information security in nonvolatile memories like PCM. The energy and endurance challenges of PCM are exacerbated when AESXTS encryption is applied. To address these challenges, we present MACE, a technique to improve the energyefficiency and lifetime of PCM in a server environment using AESXTS encryption. Additionally, we propose an architecture for MACE called WINDU which leverages inmemory, lightweight compression to reduce the auxiliary storage overhead of MACE, securing up to a 2.6 times lifetime improvement beyond existing techniques with the same area overhead. We also propose LARS, a new cradletograve energy evaluation framework that considers system lifetime. Using LARS, we provide a holistic analysis of MACE and WINDU, demonstrating how the 15% mean reduction in dynamic energy and lifetime improvements inform system design and memory selection.

TrustFS: An SGXEnabled Stackable File System Framework Data confidentiality in cloud services is commonly ensured by encrypting information before uploading it. However, this approach limits the use of contentaware functionalities, such as deduplication and compression. Although this issue has been addressed individually for some of these functionalities, no unified framework for building secure storage systems exists that can leverage such operations over encrypted data. We present TrustFS, a programmable and modular stackable file system framework for implementing secure contentaware storage functionalities over hardwareassisted trusted execution environments. This framework extends the original SafeFS architecture to provide the isolated execution guarantees of Intel SGX. We demonstrate its usability by implementing an SGXenabled stackable file system prototype while a preliminary evaluation shows that it incurs reasonable performance overhead when compared to conventional storage systems. Finally, we highlight open research challenges that must be further pursued in order for TrustFS to be fully adequate for building productionready secure storage solutions.