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copied!<p>Here is an implementation that does not require the 8 byte salt.</p> <p>You can calculate a WPA key as follows:</p> <pre><code>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(); } } } </code></pre>

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