VeritasDB: High Throughput Key-Value Store with Integrity

Applications depend on the safe operation of underlying databases. Alarmingly, cloud-backed database services face threats from exploits in the privileged computing layers (e.g. OS, Hypervisor) and attacks from rogue datacenter administrators, which tamper with the database’s storage and cause it to produce incorrect results. Although integrity verification of outsourced storage and file systems is a well-studied problem, prior techniques impose prohibitive overheads (up to 10x in throughput) and place additional responsibility on clients. We present VeritasDB, a key-value store that guarantees integrity to the client in the presence of exploits or implementation bugs in the database server. VeritasDB is implemented as a network proxy that mediates communication between the unmodified client(s) and the database server, which can be any off-the-shelf database engine (e.g., Redis, RocksDB). Since the proxy is trusted, we use security primitives offered by modern processors, such as Intel SGX enclaves, to protect the proxy’s code and state, thus completely eliminating trust on the cloud provider. To perform integrity checks in the proxy, we design an authenticated Merkle B-tree that leverages features of SGX (protected memory, direct access to unprotected memory from enclave code, and CPU parallelism) to implement several novel optimizations based on caching, concurrency, and compression. On standard YCSB and Visa transaction workloads, we observe an average overhead of 2.8x in throughput and 2.5x in latency, compared to the (insecure) system with no integrity checks — using CPU parallelism, we bring the throughput overhead further down to 1.05x. Thus, VeritasDB provides an order of magnitude improvement over existing techniques for integrity verification.