Azure SQL Database Encryption
Securing your data is paramount. Azure SQL Database offers robust encryption capabilities to protect your sensitive information at rest and in transit.
Transparent Data Encryption (TDE)
Transparent Data Encryption (TDE) encrypts data files and log files of Azure SQL Database. This is also known as "at rest" encryption. TDE automatically performs real-time encryption and decryption of the database, application, and transaction log files as they are written to and read from the disk.
Key Benefits of TDE:
- Data Protection: Protects data against threats of offline data theft by encrypting the entire database files.
- Compliance: Helps meet various regulatory and compliance requirements for data encryption.
- Ease of Use: Transparent to applications, requiring no code changes to enable encryption.
- Performance: Minimal performance overhead due to efficient implementation.
Azure SQL Database TDE can be configured using different encryption providers:
- Service-Managed Keys: Azure manages the encryption keys for you. This is the default and recommended option for most scenarios.
- Customer-Managed Keys (CMK) with Azure Key Vault: You manage your own encryption keys in Azure Key Vault, providing greater control and enabling Bring Your Own Key (BYOK) scenarios.
Always Encrypted
Always Encrypted is a security feature designed to protect sensitive data in Azure SQL Database, such as credit card numbers or national identification numbers (e.g., social security numbers), stored in the database. Always Encrypted ensures that sensitive data is always encrypted in transit and at rest in the database.
With Always Encrypted, sensitive data is encrypted using encryption keys that are accessible only by the application owner. This keeps sensitive data plain and unencrypted in a column, while the encryption operation is performed by the client driver. As a result, administrators of the database (e.g., DBAs) and other high-privilege users or auditors who have access to the database server cannot see the sensitive data in plain text.
Key Features of Always Encrypted:
- End-to-End Encryption: Protects data from the client application to the database.
- Client-Side Encryption: Encryption and decryption happen within the client application.
- Separation of Duties: Database administrators do not have access to the encryption keys.
- Column-Level Encryption: Allows selective encryption of specific columns.
Data Masking
Dynamic Data Masking (DDM) limits sensitive data exposure by masking it to non-privileged users. DDM works by transforming sensitive data into a masked format while the data in the database is not changed. It's an ideal solution for scenarios where you want to restrict access to sensitive data for users who do not need to see it, such as for querying or reporting purposes.
You can define masking rules for specific columns. For example, you can mask an email address so that only the first letter and '@' symbol are displayed, like 'a***@example.com', or mask a credit card number to show only the last four digits.
Considerations for Encryption
- Key Management: Securely managing your encryption keys is critical, whether using service-managed keys or customer-managed keys in Azure Key Vault.
- Performance Impact: While encryption is designed to be performant, very intensive workloads might experience some impact. Always test your specific scenario.
- Application Compatibility: Ensure your applications are compatible with the chosen encryption methods, especially for Always Encrypted.
For detailed implementation guides and best practices, refer to the official Azure SQL Database documentation.