How can decrypt column in SQL SP

Question

Dear All,

 

I have encrypted a table column and I want to display data decrypt data.

 

I have used below query to encrypt data. I need your help to how I can display data as it is in real.

OPEN SYMMETRIC KEY CreditCards_Key11
DECRYPTION BY CERTIFICATE Sales09;
UPDATE Sales.CreditCard
SET CardNumber_Encrypted = EncryptByKey(Key_GUID('CreditCards_Key11')
, CardNumber, 1, HashBytes('SHA1', CONVERT( varbinary
, CreditCardID)));
GO

And then the result is coming in my stored procedure is like this:-

SELECT CustomerID
AS 'Encrypted ID Number',
CONVERT(nvarchar, DecryptByKey(CustomerID))
AS 'Decrypted ID Number'
FROM tblCustomer
GO
CLOSE SYMMETRIC KEY UniqueCUSTOMERID

and the output is :-