/// <summary>
/// Calculates the MacKey (i.e. the key to use when calculating the MagTag for key confirmation).
///
/// MacKey = H(K || "JPAKE_KC")
/// </summary>
private static byte[] CalculateMacKey(BigInteger keyingMaterial, IDigest digest)
{
digest.Reset();
UpdateDigest(digest, keyingMaterial);
/*
* This constant is used to ensure that the macKey is NOT the same as the derived key.
*/
UpdateDigest(digest, "JPAKE_KC");
return DigestUtilities.DoFinal(digest);
}
/// <summary>
/// Computes hash of the data
/// </summary>
/// <param name="digest">Hash algorithm implementation</param>
/// <param name="data">Data that should be processed</param>
/// <returns>Hash of data</returns>
private static byte[] ComputeDigest(IDigest digest, byte[] data)
{
if (digest == null)
throw new ArgumentNullException("digest");
if (data == null)
throw new ArgumentNullException("data");
byte[] hash = new byte[digest.GetDigestSize()];
digest.Reset();
digest.BlockUpdate(data, 0, data.Length);
digest.DoFinal(hash, 0);
return hash;
}
private static BigInteger CalculateHashForZeroKnowledgeProof(BigInteger g, BigInteger gr, BigInteger gx,
string participantId, IDigest digest)
{
digest.Reset();
UpdateDigestIncludingSize(digest, g);
UpdateDigestIncludingSize(digest, gr);
UpdateDigestIncludingSize(digest, gx);
UpdateDigestIncludingSize(digest, participantId);
byte[] output = DigestUtilities.DoFinal(digest);
return new BigInteger(output);
}
/**
* reset the internal state
*/
public virtual void Reset()
{
digest.Reset();
}
/**
* Reset the mac generator.
*/
public virtual void Reset()
{
digest.Reset();
digest.BlockUpdate(secret, 0, secret.Length);
digest.BlockUpdate(IPAD, 0, padLength);
}
/**
* fill len bytes of the output buffer with bytes generated from
* the derivation function.
*
* @throws ArgumentException if the size of the request will cause an overflow.
* @throws DataLengthException if the out buffer is too small.
*/
public virtual int GenerateBytes(byte[] output, int outOff, int length)
{
if ((output.Length - length) < outOff)
{
throw new DataLengthException("output buffer too small");
}
long oBytes = length;
int outLen = digest.GetDigestSize();
//
// this is at odds with the standard implementation, the
// maximum value should be hBits * (2^32 - 1) where hBits
// is the digest output size in bits. We can't have an
// array with a long index at the moment...
//
if (oBytes > ((2L << 32) - 1))
{
throw new ArgumentException("Output length too large");
}
int cThreshold = (int)((oBytes + outLen - 1) / outLen);
byte[] dig = new byte[digest.GetDigestSize()];
byte[] C = new byte[4];
Pack.UInt32_To_BE((uint)counterStart, C, 0);
uint counterBase = (uint)(counterStart & ~0xFF);
for (int i = 0; i < cThreshold; i++)
{
digest.BlockUpdate(shared, 0, shared.Length);
digest.BlockUpdate(C, 0, 4);
if (iv != null)
{
digest.BlockUpdate(iv, 0, iv.Length);
}
digest.DoFinal(dig, 0);
if (length > outLen)
{
Array.Copy(dig, 0, output, outOff, outLen);
outOff += outLen;
length -= outLen;
}
else
{
Array.Copy(dig, 0, output, outOff, length);
}
if (++C[3] == 0)
{
counterBase += 0x100;
Pack.UInt32_To_BE(counterBase, C, 0);
}
}
digest.Reset();
return((int)oBytes);
}
/// <summary>Reset the internal state</summary>
public void Reset()
{
//jbonilla
currentSignature = null;
digest.Reset();
}
/// <summary> reset the internal state</summary>
public virtual void Reset()
{
contentDigest1.Reset();
}