Confidential computing with secure enclaves
As mentioned earlier, the main two challenges with Always Encrypted are the reduced query functionality and making it necessary to move data out of database for cryptographic operations, such as initial encryption or key rotation. To address this, Microsoft leverages cutting-edge secure enclave technology to allow rich computations and cryptographic operations to take place inside the database engine.
The enclave is a special, isolated, and protected region of memory. There is no way to view the data or the code inside the enclave from the outside, even with a debugger. You can think of it as a black box. This means that an enclave is the perfect place to process highly sensitive information and decrypt it, if necessary. While there are several enclave technologies available, SQL Server 2019 supports Virtualization Based Security (VBS) secure memory enclaves in Windows Server 2019. The Windows hypervisor ensures the isolation of VBS enclaves...