Microsoft® SQL Server® 2008 Bible

Chapter 51. Data Cryptography

IN THIS CHAPTER

• Introduction to cryptography

• Using the SQL Server data encryption tools

When I was a kid, I remember playing with the secret decoder ring from a cereal box. How cool was that?! Now I'm all grown up and still playing with secret decoder rings. Hmmm.

Usually, securing access to the table is sufficient; if not, securing the column will suffice. However, for some information, such as credit card numbers or secret government data, the information's sensitivity warrants further security by encrypting the data stored in the database.

SQL Server 2008 can encrypt data inside SQL Server with passwords, keys, or certificates. All editions of SQL Server support data encryption.

Introduction to Cryptography

Data encryption is basically a scrambling of the data with a secret key to produce an encoded copy of the data called the cipher data. Without the key, the data is impossible to unscramble.

Types of encryption

Symmetric encryption uses the same key to both encrypt and decrypt the data. While this method is simpler to administer and faster than asymmetric encryption, it's considered riskier because the encryption algorithm is weaker, and more tasks (people) need copies of the key. This may not be a problem when encrypting and decrypting data inside SQL Server.

What's new with data cryptography?

SQL Server 2005 introduced data encryption with master keys and certificates. Although it's complex, it was well received.

Not to rest on their laurels, for SQL Server ...