Azure Transparent Data Encryption (TDE)

1. Encryption of Data at Rest: TDE encrypts the data files of the database, including backups. This means that even if someone gains unauthorized access to the physical files, they can’t read the data without the decryption keys.

2. Automatic and Transparent: The encryption and decryption process is automatic and transparent to the application accessing the database. This means that no changes are needed to the application code, as TDE operates at the storage level.

3. Protection Against Unauthorized Access: TDE helps safeguard against unauthorized access to the data, especially in cases where the physical media (like disks or backup tapes) might be lost or stolen.

4. Key Management: TDE typically uses a hierarchical key management system, where a master encryption key (managed by the database management system) encrypts a separate database encryption key, which in turn encrypts the data. This allows for secure key management and rotation without requiring re-encryption of the data itself.

In essence, TDE provides a robust layer of security to protect sensitive data stored in a database without impacting the performance or requiring major changes to existing applications.