在C＃与Rfc2898DeriveBytes PBKDF2执行 [英] PBKDF2 implementation in C# with Rfc2898DeriveBytes
问题描述
大家好，我试图实现在C＃PBKDF2函数创建一个WPA共享密钥。我发现了一些在这里： http://msdn.microsoft.com/en-us/magazine/cc163913的.aspx 这似乎产生有效的结果，但它是一个字节太短... ...和PSK错误值。
Guys, I'm trying to implement a PBKDF2 function in C# that creates a WPA Shared key. I've found some here: http://msdn.microsoft.com/en-us/magazine/cc163913.aspx that seems to produce a valid result, but it's one byte too short... and the wrong PSK value.
要测试输出，我我把它比作是： http://www.xs4all.nl/~rjoris/wpapsk.html 或 http://anandam.name/pbkdf2/
To test the output, I am comparing it to this: http://www.xs4all.nl/~rjoris/wpapsk.html or http://anandam.name/pbkdf2/
我没有找到一个这让一起工作的方式建库到C＃叫Rfc2898DeriveBytes。用这种方法，我得到一个有效的输出使用：
I did find one way of getting this to work with a built in library to C# called Rfc2898DeriveBytes. Using this, I get a valid output using:
Rfc2898DeriveBytes k3 = new Rfc2898DeriveBytes(pwd1, salt1, 4096);
byte[] answers = k3.GetBytes(32);
现在，我一直在使用Rfc2898DeriveBytes的一个限制是盐必须是8个字节长。如果是短，Rfc2898DeriveBytes抛出异常。我想所有我做的是垫盐（如果它是短）以8个字节，我会很好的。但不是！我试过几乎每一个较短的盐填充的组合，但我不能重复的结果，我从上面这两个网站获得。
Now, the one limitation I have using Rfc2898DeriveBytes is the "salt" must be 8 octets long. If it is shorter, the Rfc2898DeriveBytes throws an exception. I was thinking all I had to do was pad the salt (if it was shorter) to 8 bytes, and I'd be good. But NO! I've tried pretty much every combination of padding with a shorter salt, but I cannot duplicate the results I get from those two websites above.
所以，底线是，不这意味着Rfc2898DeriveBytes只是简单的将不与源盐少于8个字节的工作？如果是这样，没有人知道任何C＃代码我可以使用，对于WPA预共享密钥实现PBKDF2？
So bottom line is, does this mean the Rfc2898DeriveBytes just simply won't work with a source salt shorter than 8 bytes? If so, does anyone know of any C# code I could use that implements PBKDF2 for WPA Preshared key?
推荐答案
下面是一个执行。这并不需要8个字节的盐
Here is an implementation that does not require the 8 byte salt.
您可以计算WPA密钥如下：
You can calculate a WPA key as follows:
Rfc2898DeriveBytes rfc2898 = new Rfc2898DeriveBytes(passphrase, Encoding.UTF8.GetBytes(name), 4096);
key = rfc2898.GetBytes(32);
public class Rfc2898DeriveBytes : DeriveBytes
{
const int BlockSize = 20;
uint block;
byte[] buffer;
int endIndex;
readonly HMACSHA1 hmacsha1;
uint iterations;
byte[] salt;
int startIndex;
public Rfc2898DeriveBytes(string password, int saltSize)
: this(password, saltSize, 1000)
{
}
public Rfc2898DeriveBytes(string password, byte[] salt)
: this(password, salt, 1000)
{
}
public Rfc2898DeriveBytes(string password, int saltSize, int iterations)
{
if (saltSize < 0)
{
throw new ArgumentOutOfRangeException("saltSize");
}
byte[] data = new byte[saltSize];
new RNGCryptoServiceProvider().GetBytes(data);
Salt = data;
IterationCount = iterations;
hmacsha1 = new HMACSHA1(new UTF8Encoding(false).GetBytes(password));
Initialize();
}
public Rfc2898DeriveBytes(string password, byte[] salt, int iterations) : this(new UTF8Encoding(false).GetBytes(password), salt, iterations)
{
}
public Rfc2898DeriveBytes(byte[] password, byte[] salt, int iterations)
{
Salt = salt;
IterationCount = iterations;
hmacsha1 = new HMACSHA1(password);
Initialize();
}
static byte[] Int(uint i)
{
byte[] bytes = BitConverter.GetBytes(i);
byte[] buffer2 = new byte[] {bytes[3], bytes[2], bytes[1], bytes[0]};
if (!BitConverter.IsLittleEndian)
{
return bytes;
}
return buffer2;
}
byte[] DeriveKey()
{
byte[] inputBuffer = Int(block);
hmacsha1.TransformBlock(salt, 0, salt.Length, salt, 0);
hmacsha1.TransformFinalBlock(inputBuffer, 0, inputBuffer.Length);
byte[] hash = hmacsha1.Hash;
hmacsha1.Initialize();
byte[] buffer3 = hash;
for (int i = 2; i <= iterations; i++)
{
hash = hmacsha1.ComputeHash(hash);
for (int j = 0; j < BlockSize; j++)
{
buffer3[j] = (byte) (buffer3[j] ^ hash[j]);
}
}
block++;
return buffer3;
}
public override byte[] GetBytes(int bytesToGet)
{
if (bytesToGet <= 0)
{
throw new ArgumentOutOfRangeException("bytesToGet");
}
byte[] dst = new byte[bytesToGet];
int dstOffset = 0;
int count = endIndex - startIndex;
if (count > 0)
{
if (bytesToGet < count)
{
Buffer.BlockCopy(buffer, startIndex, dst, 0, bytesToGet);
startIndex += bytesToGet;
return dst;
}
Buffer.BlockCopy(buffer, startIndex, dst, 0, count);
startIndex = endIndex = 0;
dstOffset += count;
}
while (dstOffset < bytesToGet)
{
byte[] src = DeriveKey();
int num3 = bytesToGet - dstOffset;
if (num3 > BlockSize)
{
Buffer.BlockCopy(src, 0, dst, dstOffset, BlockSize);
dstOffset += BlockSize;
}
else
{
Buffer.BlockCopy(src, 0, dst, dstOffset, num3);
dstOffset += num3;
Buffer.BlockCopy(src, num3, buffer, startIndex, BlockSize - num3);
endIndex += BlockSize - num3;
return dst;
}
}
return dst;
}
void Initialize()
{
if (buffer != null)
{
Array.Clear(buffer, 0, buffer.Length);
}
buffer = new byte[BlockSize];
block = 1;
startIndex = endIndex = 0;
}
public override void Reset()
{
Initialize();
}
public int IterationCount
{
get
{
return (int) iterations;
}
set
{
if (value <= 0)
{
throw new ArgumentOutOfRangeException("value");
}
iterations = (uint) value;
Initialize();
}
}
public byte[] Salt
{
get
{
return (byte[]) salt.Clone();
}
set
{
if (value == null)
{
throw new ArgumentNullException("value");
}
salt = (byte[]) value.Clone();
Initialize();
}
}
}
这篇关于在C＃与Rfc2898DeriveBytes PBKDF2执行的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
