Column Level Encryption can be achieved in many ways and one of the simplest ways to accomplish is by encrypting the column with a pass phrase. This is very easy way to implement as encryption and decryption can be done with the same key(symmetric).
Create Table ColumnEncrypt(SEncrypt varbinary(max))
--Encrypt the column
Insert into ColumnEncrypt(SEncrypt)
select ENCRYPTBYPASSPHRASE('My$tr@^gP@$$W0R%','This is confidental')
select * from ColumnEncrypt
--Decrypt the data
Select convert(varchar,DECRYPTBYPASSPHRASE('My$tr@^gP@$$W0R%',SEncrypt)) as [DecryptedData] from ColumnEncrypt
The Encrypted and Decrypted SQL statement is not seen in the profiler or extended event, so, other people cannot track pass phrase.
SQL Server Repository 