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Ensuring the security and integrity of data stored in SQL servers is paramount, especially in today’s digital era. One of the most efficacious ways to increase the security of your data in SQL servers is through Database Encryption. This practice, also known as ‘Protecting Data at Rest’, empowers the users to encrypt their data when stored or ‘at rest’. This post will take you through some examples of how you can implement these security measures in your SQL server.
Why Database Encryption Matters
Before we delve into the ‘how’, it’s worth understanding the ‘why’. Database encryption ensures your data is secure and uncompromised, reducing the risk of a data breach. It’s an essential aspect of any organization’s data security strategy, serving to safeguard sensitive data.
SQL Server: Transparent Data Encryption
In SQL Server, one of the most common methods for encrypting data at rest is Transparent Data Encryption (TDE). TDE automatically encrypts the entire database (data and log files) in an operation completely transparent to the client applications. Encryption of the database file is performed at the page level. The pages in an encrypted database are encrypted before they are written to disk and decrypted when read into memory.
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--Enabling TDE on SQL Server for a specific database USE master; GO CREATE MASTER KEY ENCRYPTION BY PASSWORD = '<UseStrongPasswordHere>'; go CREATE CERTIFICATE MyServerCert WITH SUBJECT = 'My DEK Certificate'; go USE AdventureWorks2012; GO CREATE DATABASE ENCRYPTION KEY WITH ALGORITHM = AES_128 ENCRYPTION BY SERVER CERTIFICATE MyServerCert; GO ALTER DATABASE AdventureWorks2012 SET ENCRYPTION ON; GO |
Here we use the CREATE MASTER KEY command to create an Encrypted Master Key, then follow it with the CREATE CERTIFICATE command to create a server certificate. Once we’ve created these, we enable TDE by associating the database with the certificate using the CREATE DATABASE ENCRYPTION KEY and ALTER DATABASE commands respectively.
Always Encrypted
Another exciting feature offered by SQL Server 2016 and later is ‘Always Encrypted’. With Always Encrypted, SQL Server offers a greater degree of protection by ensuring the data, stored within the database and used elsewhere, remains encrypted not just at rest but also during transmission and while in use.
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--To configure Always Encrypted using SQL Server Management Studio (SSMS) USE [Clinic] GO ALTER TABLE [dbo].[Patients] ALTER COLUMN [SSN] ADD MASKED WITH (FUNCTION = 'partial(0,"XXX-XX-",4)') GO |
Here, we use the ALTER COLUMN ADD MASKED command to encrypt the ‘Patients’ table’s ‘SSN’ column, showing only the last four digits to unauthorized users. This action is part of implementing the Always Encrypted feature which in turn is a part of SQL Server’s data protection strategy.
Conclusion
Through the use of in-built functions and features such as TDE and Always Encrypted, SQL Server offers robust solutions to protect your data at rest, ensuring it remains secure and uncompromised. As data becomes an increasingly valuable asset, implementing such precautions is no longer optional but a pre-requisite for any organization that values its data infrastructure.