I find this to be one of the failings of SQL Server encryption. My personal opinion is that you should handle encryption in the application, I know you don't want to do that, but I think it's the best place. If you are encrypting/decrypting in the database then the data is not secured between application and database.
If you really want it in the DB then I'd go with the CLR.
Jack Corbett
Consultant - Straight Path Solutions
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