The document describes TrustedDB, a database system that uses trusted hardware to enable private queries on outsourced data. TrustedDB allows clients to execute SQL queries while preserving privacy and regulatory compliance by leveraging tamper-proof trusted hardware for sensitive query processing stages. This removes limitations of software-only encryption approaches. The system partitions queries into public and private components, executing the latter on secure hardware for better performance and lower costs than solely cryptographic approaches. Evaluation shows TrustedDB can support full-fledged databases on trusted hardware more cost-effectively than existing techniques.