Microsoft SQL Server TDE
This document provides information about configuring HSMs with Microsoft SQL Server Transparent Data Encryption (TDE) by using Extensible Key Management (EKM) libraries. For additional questions related to your HSM, see the relevant administrator’s guide.
Microsoft SQL Server is a relational database management system (RDBMS) used for large-scale online transaction processing (OLTP), data warehousing, and e-commerce applications. It is also a business intelligence platform for data integration, analysis, and reporting solutions.
From Microsoft's documentation website: Transparent Data Encryption (TDE) encrypts SQL Server data files. This encryption is known as encrypting data at rest.
To help secure a database, you can take precautions like:
- Designing a secure system.
- Encrypting confidential assets.
- Building a firewall around the database servers.
But a malicious party who steals physical media like drives or backup tapes can restore or attach the database and browse its data.
One solution is to encrypt sensitive data in a database and use a certificate to protect the keys that encrypt the data. This solution prevents anyone without the keys from using the data. But you must plan this kind of protection in advance.
TDE does real-time I/O encryption and decryption of data and log files. The encryption uses a database encryption key (DEK). The database boot record stores the key for availability during recovery. The DEK is a symmetric key. It's secured by a certificate that the server's master database stores or by an asymmetric key that an EKM module protects.
TDE protects data at rest, which is the data and log files. It lets you follow many laws, regulations, and guidelines established in various industries. This ability lets software developers encrypt data by using AES and 3DES encryption algorithms without changing existing applications.
In this configuration, you can encrypt data by using encryption keys that only the database user can access on the external EKM HSM module.
Only the database-level items (such as the database encryption key) are user-configurable when you use TDE on SQL Database.