Secure data types: a simple abstraction for confidentiality-preserving data analytics.

Cloud computing offers a cost-efficient data analytics platform. However, due to the sensitive nature of data, many organizations are reluctant to analyze their data in public clouds. Both software-based and hardware-based solutions have been proposed to address the stalemate, yet all have substantial limitations. We observe that a main issue cutting across all solutions is that they attempt to support confidentiality in data queries in a way transparent to queries. We propose the novel abstraction of secure data types with corresponding annotations for programmers to conveniently denote constraints relevant to security. These abstractions are leveraged by novel compilation techniques in our system Cuttlefish to compute data analytics queries in public cloud infrastructures while keeping sensitive data confidential. Cuttlefish encrypts all sensitive data residing in the cloud and employs partially homomorphic encryption schemes to perform operations securely, resorting however to client-side completion, re-encryption, or secure hardware-based re-encryption based on Intel's SGX when available based on a novel planner engine. Our evaluation shows that our prototype can execute all queries in standard benchmarks such as TPC-H and TPC-DS with an average overhead of 2.34× and 1.69× respectively compared to a plaintext execution that reveals all data.