对称加密密钥通过行为

Question

我刚刚运行以下测试，我深感困惑：

我创建了一个表，如下所示：

CREATE TABLE [dbo].[enxtest](
    [id] [int] NOT NULL, 
    [cleara] [varchar](50) NULL, 
    [encrypta] [varbinary](2000) NULL, 
    [clearb] [varchar](50) NULL, 
CONSTRAINT [PK_enxtest] PRIMARY KEY CLUSTERED 
(
    [id] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) ON [PRIMARY] 

GO 

我用数据填充它像这样：

id | cleara  | encrypta | clearb 
1 | teststring!1 | NULL  | NULL 
2 | teststring!1 | NULL  | NULL 
3 | teststring!2 | NULL  | NULL 
4 | teststring!2 | NULL  | NULL 

我使用SQL Server对称密钥和证书对像这样（唯一相关的代码，SPROC内部）并插入加密值成e运行脚本以每次cleara，一个的内容进行加密ncrypta场：

OPEN SYMMETRIC KEY THIS_IS_THE_KEY 
    DECRYPTION BY CERTIFICATE THIS_IS_THE_CERT 
CONVERT(varbinary(2000), EncryptByKey(Key_GUID('THIS_IS_THE_KEY'), cleara), 1) 

然后，我们删除了数据库主密钥，对称密钥和证书以及重建他们，给予他们收到了相同的名称。我运行了一个脚本来解密varbinary，类似于上面的加密代码，并将其插入到clearb中。

该查询给我下面的结果：

SELECT id, cleara, clearb 
FROM enxtest; 

id | cleara  | encrypta | clearb 
1 | teststring!1 | NULL  | teststring!1 
2 | teststring!1 | NULL  | teststring!1 
3 | teststring!2 | NULL  | teststring!2 
4 | teststring!2 | NULL  | teststring!2 

问题：

1. 这怎么可能？我期待得到clearb == clearb，但是 clearb！= cleara。我希望切换出来的键会产生 始终不正确的varchar值。
2. 有没有办法将备份恢复到另一台服务器，同时保持表中的二进制数据不变，创建新的密钥可以可靠地解密该数据，使其一致但不正确（与原始的明文值）值？

编辑：这是我们分批运行的完整脚本。

--Batch 1 
declare @e1 varbinary(2000); 
declare @c1 varchar(50); 
select @c1 = cleara from enxtest where id = 1; 
exec dbo.spEncryptString @cleartextString = @c1, @encryptedString = @e1 OUTPUT; 

declare @e2 varbinary(2000); 
declare @c2 varchar(50); 
select @c2 = cleara from enxtest where id = 2; 
exec dbo.spEncryptString @cleartextString = @c2, @encryptedString = @e2 OUTPUT; 

declare @e3 varbinary(2000); 
declare @c3 varchar(50); 
select @c3 = cleara from enxtest where id = 3; 
exec dbo.spEncryptString @cleartextString = @c3, @encryptedString = @e3 OUTPUT; 

declare @e4 varbinary(2000); 
declare @c4 varchar(50); 
select @c4 = cleara from enxtest where id = 4; 
exec dbo.spEncryptString @cleartextString = @c4, @encryptedString = @e4 OUTPUT; 

update enxtest 
set encrypta = @e1 
where id = 1; 

update enxtest 
set encrypta = @e2 
where id = 2; 

update enxtest 
set encrypta = @e3 
where id = 3; 

update enxtest 
set encrypta = @e4 
where id = 4; 


/* 
--Batch 2 
drop symmetric key THIS_IS_THE_KEY; 
drop certificate THIS_IS_THE_CERT; 
drop master key; 

create master key encryption by password = 'somepassword'; 
create certificate THIS_IS_THE_CERT with subject = 'subject' expiry_date = '20161231'; 
create symmetric key THIS_IS_THE_KEY with algorithm = AES_256 
    key_source = 'source' identity_value = 'identity' encryption by certificate THIS_IS_THE_CERT; 
*/ 

--Batch 3 
declare @e1 varbinary(2000); 
declare @c1 varchar(50); 
select @e1 = encrypta from enxtest where id = 1; 
exec dbo.spDecryptString @encryptedString = @e1, @cleartextString = @c1 OUTPUT; 

declare @e2 varbinary(2000); 
declare @c2 varchar(50); 
select @e2 = encrypta from enxtest where id = 2; 
exec dbo.spDecryptString @encryptedString = @e2, @cleartextString = @c2 OUTPUT; 

declare @e3 varbinary(2000); 
declare @c3 varchar(50); 
select @e3 = encrypta from enxtest where id = 3; 
exec dbo.spDecryptString @encryptedString = @e3, @cleartextString = @c3 OUTPUT; 

declare @e4 varbinary(2000); 
declare @c4 varchar(50); 
select @e4 = encrypta from enxtest where id = 4; 
exec dbo.spDecryptString @encryptedString = @e4, @cleartextString = @c4 OUTPUT; 

update enxtest 
set clearb = @c1 
where id = 1; 

update enxtest 
set clearb = @c2 
where id = 2; 

update enxtest 
set clearb = @c3 
where id = 3; 

update enxtest 
set clearb = @c4 
where id = 4; 

--Check 
select * from enxtest; 

Answer 1

您没有完全生成repro脚本（例如，我没有存储过程的主体），但是我看到了问题。当您使用相同的KEY_SOURCE参数创建对称密钥时，基本上就是创建完全相同的密钥。一旦你知道了，修复很容易 - 每次创建密钥时为KEY_SOURCE提供一个不同的值。