Column level encryption usually has seriously performance issues b'coz columns are encrypted, indexes won't work, ended up with slow and I/O intensive table scans. Plus you do want a good key management solution. Encryption without key management is worse than without any. Take a look at storage/file encryption security products from Bloombase, Brocade or Thales. Simply migrate your TSQL data files and access via these encryption servers, off you go with secured data store. One thing I know is they are quite expensive so check your corporate budget.