DECRYPTBYASYMKEY（）不返回预期值 [英] DECRYPTBYASYMKEY() Not Returning Expected Value

问题描述

我正在玩不对称加密和解密，但是我不明白当我尝试解密值时得到的结果。

为什么这样：

  CREATE ASYMMETRIC KEY myasymkey 
 WITH ALGORITHM = RSA_2048 
加密PASSWORD ='123pass！'; 
 GO 
 
 SELECT DECRYPTBYASYMKEY（ASYMKEY_ID（'myasymkey'），
 EncryptByAsymKey（AsymKey_ID（'myasymkey'），'Greg'），
 N'123pass！ ）; 
 GO 
  

生产 0x47726567 ？我期待它是 Greg 。

更新：我很笨， 0x47726567 从 varbinary 转换为 Greg

解决方案

这是正确的 - 当你加密一些被视为一个字节数组的东西，并且被返回。 0x47是G，72是r等。

如果您检查 DecryptByAsmKey ，你会注意到返回类型是varbinary，最大大小为8,000字节。你也会注意到这个例子中的转换。

所以如果你正在加密和解密字符串，你必须像这样转换

pre> SELECT CONVERT（varchar（max），DECRYPTBYASYMKEY（ASYMKEY_ID（'myasymkey'））
EncryptByAsymKey（AsymKey_ID（'myasymkey'），
'Greg' ），
N'123pass！'））;


另请注意，您需要确保转换为varchar（max）或nvarchar（max）取决于您的输入。如果您尝试

  SELECT CONVERT（nvarchar（max），DECRYPTBYASYMKEY（ASYMKEY_ID（'myasymkey'））
 EncryptByAsymKey AsymKey_ID（'myasymkey'），
'Greg'），
 N'123pass！'））; 
  

这将是错误的，因为您的Greg的输入是varchar。

I'm playing around with Asymmetric Encryption and Decryption, but I don't understand the results I'm getting when I try to decrypt values.

Why does this:

CREATE ASYMMETRIC KEY myasymkey 
    WITH ALGORITHM = RSA_2048 
    ENCRYPTION BY PASSWORD = '123pass!'; 
GO

SELECT DECRYPTBYASYMKEY(ASYMKEY_ID('myasymkey'), 
    EncryptByAsymKey(AsymKey_ID('myasymkey'), 'Greg'), 
    N'123pass!');
GO

Produce 0x47726567? I was expecting it to be Greg.

UPDATE: I'm dumb, 0x47726567 is Greg when converted from varbinary.

解决方案

It's right - when you encrypt something it's treated as a byte array and is returned as such. 0x47 is G, 72 is r etc.

If you examine the documentation for DecryptByAsmKey you'll notice the return type is varbinary with a maximum size of 8,000 bytes. You'll also notice the convert in the example.

So if you are encrypting and decrypting strings you must convert like so

SELECT CONVERT(varchar(max),DECRYPTBYASYMKEY(ASYMKEY_ID('myasymkey'), 
    EncryptByAsymKey(AsymKey_ID('myasymkey'), 
    'Greg'), 
    N'123pass!'));

Also note you need to make sure you're converting to varchar(max) or nvarchar(max) depending on your input. If you tried

SELECT CONVERT(nvarchar(max),DECRYPTBYASYMKEY(ASYMKEY_ID('myasymkey'), 
    EncryptByAsymKey(AsymKey_ID('myasymkey'), 
    'Greg'), 
    N'123pass!'));

it would be wrong, as your input of 'Greg' is a varchar.

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