经过几小时和几小时的代码,我发现最简单的方法是在Pkcs5S2ParametersGenerator.cs中获取代码的几个部分并创建自己的类,当然使用其他BouncyCastle API的。这适用于DotNet Compact Framework(Windows Mobile)。这相当于Rfc2898DeriveBytes类,它不在DotNet Compact Framework 2.0/3.5中。好吧,也许不是完全等效,但做这项工作:)
这是PKCS5/PKCS#5
这是用来将HMAC-SHA1
第一件事情PRF(伪随机函数)第一。从http://www.bouncycastle.org/csharp/下载Bouncy Castle编译程序集,将BouncyCastle.Crypto.dll
作为参考添加到您的项目中。
之后,用下面的代码创建新的类文件。
using System;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Crypto.Digests;
using Org.BouncyCastle.Crypto.Macs;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Security;
namespace PBKDF2_PKCS5
{
class PBKDF2
{
private readonly IMac hMac = new HMac(new Sha1Digest());
private void F(
byte[] P,
byte[] S,
int c,
byte[] iBuf,
byte[] outBytes,
int outOff)
{
byte[] state = new byte[hMac.GetMacSize()];
ICipherParameters param = new KeyParameter(P);
hMac.Init(param);
if (S != null)
{
hMac.BlockUpdate(S, 0, S.Length);
}
hMac.BlockUpdate(iBuf, 0, iBuf.Length);
hMac.DoFinal(state, 0);
Array.Copy(state, 0, outBytes, outOff, state.Length);
for (int count = 1; count != c; count++)
{
hMac.Init(param);
hMac.BlockUpdate(state, 0, state.Length);
hMac.DoFinal(state, 0);
for (int j = 0; j != state.Length; j++)
{
outBytes[outOff + j] ^= state[j];
}
}
}
private void IntToOctet(
byte[] Buffer,
int i)
{
Buffer[0] = (byte)((uint)i >> 24);
Buffer[1] = (byte)((uint)i >> 16);
Buffer[2] = (byte)((uint)i >> 8);
Buffer[3] = (byte)i;
}
// Use this function to retrieve a derived key.
// dkLen is in octets, how much bytes you want when the function to return.
// mPassword is the password converted to bytes.
// mSalt is the salt converted to bytes
// mIterationCount is the how much iterations you want to perform.
public byte[] GenerateDerivedKey(
int dkLen,
byte[] mPassword,
byte[] mSalt,
int mIterationCount
)
{
int hLen = hMac.GetMacSize();
int l = (dkLen + hLen - 1)/hLen;
byte[] iBuf = new byte[4];
byte[] outBytes = new byte[l * hLen];
for (int i = 1; i <= l; i++)
{
IntToOctet(iBuf, i);
F(mPassword, mSalt, mIterationCount, iBuf, outBytes, (i - 1) * hLen);
}
//By this time outBytes will contain the derived key + more bytes.
// According to the PKCS #5 v2.0: Password-Based Cryptography Standard (www.truecrypt.org/docs/pkcs5v2-0.pdf)
// we have to "extract the first dkLen octets to produce a derived key".
//I am creating a byte array with the size of dkLen and then using
//Buffer.BlockCopy to copy ONLY the dkLen amount of bytes to it
// And finally returning it :D
byte[] output = new byte[dkLen];
Buffer.BlockCopy(outBytes, 0, output, 0, dkLen);
return output;
}
}
}
那么如何使用这个函数呢?简单! :) 这是一个非常简单的例子,其中密码和salt由用户提供。
private void cmdDeriveKey_Click(object sender, EventArgs e)
{
byte[] salt = ASCIIEncoding.UTF8.GetBytes(txtSalt.Text);
PBKDF2 passwordDerive = new PBKDF2();
// I want the key to be used for AES-128, thus I want the derived key to be
// 128 bits. Thus I will be using 128/8 = 16 for dkLen (Derived Key Length) .
//Similarly if you wanted a 256 bit key, dkLen would be 256/8 = 32.
byte[] result = passwordDerive.GenerateDerivedKey(16, ASCIIEncoding.UTF8.GetBytes(txtPassword.Text), salt, 1000);
//result would now contain the derived key. Use it for whatever cryptographic purpose now :)
//The following code is ONLY to show the derived key in a Textbox.
string x = "";
for (int i = 0; i < result.Length; i++)
{
x += result[i].ToString("X");
}
txtResult.Text = x;
}
如何检查这是否正确? 有一个在线的JavaScript PBKDF2 http://anandam.name/pbkdf2/
的执行我得到一致的结果:) 请报告,如果有人越来越不正确的结果:)
希望这可以帮助别人:)
更新:已确认与测试向量的工作提供了这里
http://tools.ietf.org/html/draft-josefsson-pbkdf2-test-vectors-00
UPDAT E: 或者,对于盐,我们可以使用RNGCryptoServiceProvider
。确保引用System.Security.Cryptography
名称空间。
RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
byte[] salt = new byte[16];
rng.GetBytes(salt);
你很快回答你自己的问题! – 2010-07-09 23:28:23
你刚刚为我节省了很多时间。谢谢! – John 2011-01-20 17:10:55
@John:很高兴能有任何帮助:) – 2011-01-21 01:00:39