David Fowler walks us through the various keys used in encrypting data in SQL Server:
I’m sure that we all know that SQL Server includes all sorts of interesting functionality to allow us to encrypt our data and like with all encryption techniques, that data is encrypted using keys.
In SQL Server we’ve got a number of different keys, we’ve got the Service Master Key, Database Master Keys, Symmetric Keys, Asymmetric Keys and Certificates. These keys can be used to encrypt data but they can also be used to encrypt other keys and this is where the key hierarchy comes in.
Warning: it’s turtles all the way down.