Encryption in SQL Server

 Encryption in SQL Server is essential for protecting sensitive data. SQL Server offers several encryption mechanisms to secure data at rest and in transit. Here are the primary encryption features available in SQL Server:

1. Transparent Data Encryption (TDE)

• Purpose: Encrypts the entire database, including the database files (data and log files).
• How it works: Encrypts data at the page level as it is written to disk. When read, the data is decrypted.
• Use case: Protecting data at rest to ensure that files cannot be read if accessed outside the database environment.

2. Column-Level Encryption

• Purpose: Encrypts specific columns within a table.
• How it works: Uses encryption algorithms to encrypt data in specified columns.
• Use case: Protecting sensitive information such as credit card numbers or social security numbers.

3. Always Encrypted

• Purpose: Encrypts sensitive data within client applications.
• How it works: Data is encrypted at the client side and stored in an encrypted form in the database. Encryption keys are never exposed to the SQL Server.
• Use case: Ensuring that SQL Server administrators or other unauthorized users cannot view sensitive data.

4. Dynamic Data Masking (DDM)

• Purpose: Masks sensitive data in query results.
• How it works: Masks data dynamically when queries are executed, providing obfuscated results to users who do not have permission to view the original data.
• Use case: Limiting exposure of sensitive data to non-privileged users.

5. Transport Layer Security (TLS)

• Purpose: Encrypts data transmitted between SQL Server and client applications.
• How it works: Uses SSL/TLS protocols to encrypt data in transit.
• Use case: Protecting data from eavesdropping and tampering during transmission.