public KdfResult DeriveKey(BitString salt, string password, int c, int keyLen)
{
// Could check keyLen, but the allowed max is larger than an int allows, so we just force positive...
if (keyLen <= 0)
{
return(new KdfResult("KeyLen must be greater than 0"));
}
var passwordBytes = Encoding.ASCII.GetBytes(password);
var iterationsNeeded = keyLen.CeilingDivide(_hmac.OutputLength);
var saltBytes = salt.GetPaddedBytes();
var t = new byte[GetNextMultiple(keyLen, _hmac.OutputLength) / 8];
var u = new byte[_hmac.OutputLength / 8];
var t_i = new byte[_hmac.OutputLength / 8];
_hmac.Init(passwordBytes);
for (var i = 1; i <= iterationsNeeded; i++)
{
var iterationCounter = new byte[4];
iterationCounter[0] = (byte)(i >> 24);
iterationCounter[1] = (byte)(i >> 16);
iterationCounter[2] = (byte)(i >> 8);
iterationCounter[3] = (byte)i;
//Array.Copy(saltBytes, u, saltBytes.Length);
//Array.Copy(iterationCounter, 0, u, saltBytes.Length, 4);
Array.Clear(t_i, 0, t_i.Length);
for (var j = 1; j <= c; j++)
{
_hmac.FastInit();
if (j == 1)
{
_hmac.Update(saltBytes, salt.BitLength);
_hmac.Update(iterationCounter, iterationCounter.Length * 8);
}
else
{
_hmac.Update(u, u.Length * 8);
}
_hmac.Final(ref u);
for (var k = 0; k < u.Length; k++)
{
t_i[k] ^= u[k];
}
}
Array.Copy(t_i, 0, t, (i - 1) * t_i.Length, t_i.Length);
}
return(new KdfResult(new BitString(t).GetMostSignificantBits(keyLen)));
}
public HashResult HashMessage(BitString message, int outLen = 0)
{
var digest = new byte[48];
Init();
Update(message.GetPaddedBytes(), message.BitLength);
Final(digest);
return(new HashResult(new BitString(digest)));
}
public MacResult Generate(BitString key, BitString message, int macLength = 0)
{
Init(key.GetPaddedBytes());
Update(message.GetPaddedBytes(), message.BitLength);
var result = new byte[_processingLen / 8];
Final(ref result, 0);
if (macLength == 0 || macLength == OutputLength)
{
return(new MacResult(new BitString(result)));
}
return(new MacResult(new BitString(result).GetMostSignificantBits(macLength)));
}
public HashResult HashMessage(BitString message, int outLen = 0)
{
if (outLen == 0)
{
outLen = _bitLength;
}
// If outputBitLength is not a multiple of 8, make it one
var requestedBitLength = outLen;
if (outLen % 8 != 0)
{
outLen += 8 - (outLen % 8);
}
var digest = new byte[outLen / 8];
Init();
Update(message.GetPaddedBytes(), message.BitLength);
Final(digest, outLen);
return(requestedBitLength == outLen ? new HashResult(new BitString(digest)) : new HashResult(LittleEndianSubstring(new BitString(digest), 0, requestedBitLength)));
}
