Verification system and methods are provided for allowing database server responses to be verified. A proxy device may maintain a data structure (e.g., a Merkle B+-tree) within a secure memory space (e.g., an Intel SGX enclave) associated with a protected application. In some embodiments, the data structure may comprise hashed values representing hashed versions of the data managed by the database server. The proxy may intercept client requests submitted from a client device and forward such requests to the database server. Responses from the database server may be verified using the data structure (e.g., the hashes contained in the Merkle B+-tree). If the data is verified by the proxy device, the response may be transmitted to the client device.