I have been asked several times what SharePoint ability to encrypt  data that resides the SQL Server databases. I was answering this  question when I ran across this awesome presentation that I highly  recommend. “SQL Transparent Data Encryption for SharePoint Content  Databases” at http://technet.microsoft.com/en-us/edge/Video/ff711430. Just want the first few minutes of the video.
Smaller notes I usually bring up are:
· Row level encryption is not really possible as we do encryption at the database level.
·  An important note is that the SQL connection from the SharePoint  application layer to SQL server is done through a service account. Users  are not directly authenticating and accessing data in the database.
·  Documents themselves can have rights management applied so the BLOB is  encrypted when it is stored in SharePoint. However metadata associated  to the document is not encrypted and documents will not be searchable.
Using Transparent Data Encryption really is a great solution.
