In Microsoft SQL Server 2008/2012 Enterprise edition users can enable Extensible Key Management (EKM) and use either TDE or cell level encryption to encrypt their sensitive data and to be selective about the data they encrypt. EKM is an architecture that allows users to incorporate a third-party* encryption key management hardware security module (HSM) in order to truly secure their data using key management best practices and meet compliance regulations.
*Townsend Security is a Microsoft Silver partner and provider of encryption key management HSMs for Microsoft SQL Server, Microsoft SharePoint, Windows, and Microsoft Azure.
Users select from one of the two methods of SQL Server encryption available for the Microsoft SQL Server 2008/2012 Enterprise Edition and above:
1) Transparent Data Encryption (TDE): TDE encrypts the entire database and temporary files within that space with no additional programming.
On earlier versions of SQL Server deploying encryption had been a much larger and more complicated programming project. With 2008/2012 Enterprise edition, TDE can be implemented fully without any programing at all. Once your administrator has DBA administrative rights, he or she can implement TDE through a straightforward process that requires no changes to coding, queries, or applications. TDE is a favored way to rapidly encrypt data and works well for small or medium sized databases because of its speed and ease of deployment.
2) Cell Level Encryption: Cell Level Encryption allows database administrators to select the columns they wish to encrypt in a database - a benefit for many administrators with larger databases; however, this process takes a little bit more effort to set up.
If you are leveraging EKM and using an external encryption key manager, the database administrator can encrypt data in the column (cell level) by adding a modifier on a particular fetch or update to the database. However, administrators will need to make small changes to their databases to enable their encryption key manager to do this. This is not a complicated step, however, and your encryption key management vendor should be able to help you through this. Cell level encryption works well for large databases where performance impacts must be kept to a minimum and only certain data needs to be encrypted.
Here is a very straightforward YouTube demonstration video where you can see just how easily TDE is set up.
Setting Up TDE & EKM on SQL Server 2008 / 2012 for Compliance
For a more in-depth look, we have compiled a selection of resources (webinar, white paper, podcast) that can provide additional information: