/// <summary>
/// Updates internal state with data from the provided array.
/// </summary>
/// <param name="data">Array of bytes</param>
/// <param name="index">Offset of byte sequence</param>
/// <param name="length">Sequence length</param>
public void Update(byte[] data, int index, int length)
{
Array16 <ulong> block;
int bytesInBuffer = (int)_totalBytes & (BlockSize - 1);
_totalBytes += (uint)length;
if (_totalBytes >= ulong.MaxValue / 8)
{
throw new InvalidOperationException("Too much data");
}
// Fill existing buffer
if (bytesInBuffer != 0)
{
var toCopy = Math.Min(BlockSize - bytesInBuffer, length);
Buffer.BlockCopy(data, index, _buffer, bytesInBuffer, toCopy);
index += toCopy;
length -= toCopy;
bytesInBuffer += toCopy;
if (bytesInBuffer == BlockSize)
{
ByteIntegerConverter.Array16LoadBigEndian64(out block, _buffer, 0);
Sha512Internal.Core(out _state, ref _state, ref block);
CryptoBytes.InternalWipe(_buffer, 0, _buffer.Length);
bytesInBuffer = 0;
}
}
// Hash complete blocks without copying
while (length >= BlockSize)
{
ByteIntegerConverter.Array16LoadBigEndian64(out block, data, index);
Sha512Internal.Core(out _state, ref _state, ref block);
index += BlockSize;
length -= BlockSize;
}
// Copy remainder into buffer
if (length > 0)
{
Buffer.BlockCopy(data, index, _buffer, bytesInBuffer, length);
}
}
public static bool crypto_sign_verify(
byte[] sig, int sigoffset,
byte[] m, int moffset, int mlen,
byte[] pk, int pkoffset)
{
byte[] h;
byte[] checkr = new byte[32];
GroupElementP3 A;
GroupElementP2 R;
if ((sig[sigoffset + 63] & 224) != 0)
{
return(false);
}
if (GroupOperations.ge_frombytes_negate_vartime(out A, pk, pkoffset) != 0)
{
return(false);
}
var hasher = new Sha512();
hasher.Update(sig, sigoffset, 32);
hasher.Update(pk, pkoffset, 32);
hasher.Update(m, moffset, mlen);
h = hasher.Finalize();
ScalarOperations.sc_reduce(h);
var sm32 = new byte[32];
Array.Copy(sig, sigoffset + 32, sm32, 0, 32);
GroupOperations.ge_double_scalarmult_vartime(out R, h, ref A, sm32);
GroupOperations.ge_tobytes(checkr, 0, ref R);
var result = CryptoBytes.ConstantTimeEquals(checkr, 0, sig, sigoffset, 32);
CryptoBytes.Wipe(h);
CryptoBytes.Wipe(checkr);
return(result);
}
