CREATE MASTER KEY ENCRYPTION BY PASSWORD = '??xxx'

CREATE SYMMETRIC KEY dcmy 
WITH ALGORITHM = DES 
ENCRYPTION BY PASSWORD = 'xxx??'

--打开对称密钥
OPEN SYMMETRIC KEY dcmy  DECRYPTION BY PASSWORD = 'xxx??'

--以加密的方式存放数据
INSERT INTO [tb_Teacher] (TeaName,TeaPwd) VALUES 
(
'老师五',

EncryptByKey(Key_GUID('dcmy'), '456456')

)

select * from tb_Teacher

select CONVERT(varchar, DecryptByKey(TeaPwd)) from tb_Teacher

create table [tb_Teacher]
(TeaName nvarchar(20)
,TeaPwd nvarchar(200));
GO

CREATE SYMMETRIC KEY dcmy 
WITH ALGORITHM = DES 
ENCRYPTION BY PASSWORD = '1234567890'

--打开对称密钥
OPEN SYMMETRIC KEY dcmy  DECRYPTION BY PASSWORD = '1234567890'


--以加密的方式存放数据
INSERT INTO [tb_Teacher] (TeaName,TeaPwd) VALUES 
(
'老师五',

EncryptByKey(Key_GUID('dcmy'), '456456')

)

select * from tb_Teacher
/*
TeaName              TeaPwd
-------------------- -----------------
老师五                  ?菮??劦洼??
 ????娺簍????
*/
select CONVERT(varchar, DecryptByKey(TeaPwd)) from tb_Teacher
/*
456456
*/