RSA.ImportParameters()中的CryptographicException-特殊1024键中的错误数据 [英] CryptographicException in RSA.ImportParameters() - Bad Data in special 1024 keys

问题描述

我们有一个C#/.Net 4.0应用程序，该应用程序从WebService中收到的Base64中的字符串中导入RSA私钥.

We have a C#/.Net 4.0 application which imports RSA Private Keys from a String in Base64 received in a WebService.

此应用程序非常适合1024位RSA密钥，但不适用于特殊类型的rsa私钥(约占密钥的1％).

This application works perfectly for RSA-Keys in 1024 bits, but doesn't with a special kind of rsa private keys (around 1% of keys).

以下是字节长度:

工作键:

• 模数=> 128字节
• 指数=> 3个字节
• D => 128字节
• P => 64字节
• Q => 64字节
• DP => 64字节
• DQ => 64字节
• IQ => 64字节

不工作键:

• 模数=> 128字节
• 指数=> 3个字节
• D => 127字节
• P => 64字节
• Q => 64字节
• DP => 64字节
• DQ => 64字节
• IQ => 64字节

• Modulus => 128 Bytes
• Exponent => 3 Bytes
• D => 127 Bytes
• P => 64 Bytes
• Q => 64 Bytes
• DP => 64 Bytes
• DQ => 64 Bytes
• IQ => 64 Bytes

区别在于D的长度(128个有效，127个无效).非工作密钥比工作密钥短1个字节.

The difference is in the lenght of D (128 working, 127 not working). The not-working key is 1 byte shorter than the working key.

已设置参数，但是在执行RSA.ImportParameters(rsaParams)时会引发带有"Bad Data"消息的CryptographicException.

The parameters are set but when doing RSA.ImportParameters(rsaParams) it throws a CryptographicException with a "Bad Data" Message.

解决这个问题应该包括什么?

What should be included to solve this problem?

推荐答案

RSACryptoServiceProvider对数据长度有一些假设，即:

RSACryptoServiceProvider has some assumptions on the data lengths which are:

• 模量:任何偶数大小，我们称其长度为n
• 指数:(<= 4个字节；尽管RSACng允许任何大小")，我们将其称为长度e
• D:n
• P:n/2
• 问:n/2
• DP:n/2
• DQ:n/2
• InverseQ:n/2

• Modulus: any even size, let's call the length n
• Exponent: (<= 4 bytes; though RSACng allows "any size"), let's call the length e
• D: n
• P: n/2
• Q: n/2
• DP: n/2
• DQ: n/2
• InverseQ: n/2

因此，假设您的第二个键实际上是模量:128字节(因为64字节的P乘以64字节的Q并不是256字节的数字)，您只需要用零以使其达到适当的长度.

So, assuming that your second key is actually Modulus: 128 bytes (because a 64-byte P times a 64-byte Q isn't a 256 byte number), you just need to left-pad the D array with a zero to bring it up to the proper length.

byte[] newD = new byte[modulus.Length];
Buffer.BlockCopy(d, 0, newD, newD.Length - d.Length, d.Length);

.NET Core具有

.NET Core has the source code available showing that relationship. In .NET Framework it's buried inside the CLR, so not available on referencesource.

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