Transparent Data Encryption (TDE) is a feature in SQL Server that enables encryption of the database files at rest. With TDE, you can protect sensitive data such as credit card information, social security numbers, and proprietary information in case your database files are stolen, hacked, or misplaced.
To enable TDE in your SQL Server database, follow these steps:
1. Create a master key:
USE master;
CREATE MASTER KEY ENCRYPTION BY PASSWORD = '<password>';Here, you are creating a master key that will be used to protect the encryption key.
2. Create a certificate:
CREATE CERTIFICATE MyServerCert
WITH SUBJECT = 'My Server Certificate';This certificate will be used to protect the encryption key.
3. Backup the certificate:
BACKUP CERTIFICATE MyServerCert TO FILE = '<path>'
WITH PRIVATE KEY (FILE = '<path>', ENCRYPTION BY PASSWORD = '<password>');This step is important as you need to keep a copy of the certificate in a safe location. The certificate will be used to decrypt the encryption key in case of server failure.
4. Create a database encryption key:
USE <database>;
CREATE DATABASE ENCRYPTION KEY
WITH ALGORITHM = AES_256
ENCRYPTION BY SERVER CERTIFICATE MyServerCert;Here, you are creating a database encryption key that will be used to encrypt the data in your database. The key is protected by the certificate you created earlier.
5. Turn on encryption:
ALTER DATABASE <database> SET ENCRYPTION ON;Finally, you turn on encryption for your database.
After following these steps, your database encryption key is encrypted with the server certificate, which is protected by the master key. Your entire database, including table data, indexes, and temporary files, is encrypted at rest.
It is important to note that TDE does not protect data in transit, such as when it is being transmitted from an application to the server or from one server to another. For that, you would need to use other encryption methods such as SSL/TLS.