Control: Azure > CIS v2.0 > 04 - Database Services > 4.01 SQL Server - Auditing > 4.01.03 - Ensure SQL server's Transparent Data Encryption (TDE) protector is encrypted with Customer-managed key

Configures auditing against a CIS Benchmark item.

Level: 2

Transparent Data Encryption (TDE) with Customer-managed key support provides increased transparency and control over the TDE Protector, increased security with an HSM-backed external service, and promotion of separation of duties. With TDE, data is encrypted at rest with a symmetric key (called the database encryption key) stored in the database or data warehouse distribution. To protect this data encryption key (DEK) in the past, only a certificate that the Azure SQL Service managed could be used. Now, with Customer-managed key support for TDE, the DEK can be protected with an asymmetric key that is stored in the Azure Key Vault. The Azure Key Vault is a highly available and scalable cloud-based key store which offers central key management, leverages FIPS 140-2 Level 2 validated hardware security modules (HSMs), and allows separation of management of keys and data for additional security.

Based on business needs or criticality of data/databases hosted on a SQL server, it is recommended that the TDE protector is encrypted by a key that is managed by the data owner (Customer-managed key).