\(Enc^2\) DB: A Hybrid and Adaptive Encrypted Query Processing Framework

Cloud computing has become an essential infrastructure for efficient data management systems. Following the framework, data owners are now outsourcing their data to cloud service providers (CSP), which shall then be expected to provide Database Service (DBaaS). This change in database usage brings in a deviation of data ownership and usage, leading to inevitable privacy issues that prevent users from outsourcing database services to CSPs. Existing solutions to this problem rely on either property-preserving cryptography schemes or a trusted execution environment (TEE). However, either solution suffers from a series of limitations. In light of this, we propose and implement a framework, namely \(Enc^2\) DB, following a hybrid strategy that preserves the pros of both types of approaches. Within the system, we present a micro-benchmarking test and a self-adaptive mode switch strategy that can dynamically choose the best execution path, cryptography or TEE, to answer a given query. We implement the framework over a pair of off-the-shelf rdbmss. Empirical study over TPC-C justifies that \(Enc^2\) DB outperforms existing TEE or cryptographic solutions.