Execute the following script in Query Editor to demonstrate the use of varbinary(max):

USE AdventureWorks

CREATE CERTIFICATE CertificateZ
ENCRYPTION BY PASSWORD = '007$$$A'
WITH SUBJECT ='CertificateZ',
START_DATE = '2005/01/01',
EXPIRY_DATE = '2010/01/01'

DECLARE @CypherText varbinary(MAX)
SET @CypherText = EncryptByCert(Cert_ID('CertificateZ'),'SQLUSA')

SELECT Cypher=@CypherText,
Decyphered=convert(varchar,DecryptByCert(Cert_ID('CertificateZ'),@CypherText, N'007$$$A' ))