public void Reset(byte[] key)
{
if (key.Length != 32)
{
throw new ArgumentException("Poly1305 key must be 256 bits.");
}
bufferLength = 0;
h0 = h1 = h2 = h3 = h4 = 0;
// Extract r portion of key (and "clamp" the values)
uint t0 = Lend.Pack32(key, 0);
uint t1 = Lend.Pack32(key, 4);
uint t2 = Lend.Pack32(key, 8);
uint t3 = Lend.Pack32(key, 12);
// NOTE: The masks perform the key "clamping" implicitly
r0 = t0 & 0x03FFFFFFU;
r1 = ((t0 >> 26) | (t1 << 6)) & 0x03FFFF03U;
r2 = ((t1 >> 20) | (t2 << 12)) & 0x03FFC0FFU;
r3 = ((t2 >> 14) | (t3 << 18)) & 0x03F03FFFU;
r4 = (t3 >> 8) & 0x000FFFFFU;
// Precompute multipliers
s1 = r1 * 5;
s2 = r2 * 5;
s3 = r3 * 5;
s4 = r4 * 5;
k0 = Lend.Pack32(key, BLOCK_SIZE + 0);
k1 = Lend.Pack32(key, BLOCK_SIZE + 4);
k2 = Lend.Pack32(key, BLOCK_SIZE + 8);
k3 = Lend.Pack32(key, BLOCK_SIZE + 12);
}
private static void StateInit(uint[] state, byte[] key, byte[] nonce)
{
Array.Clear(state, 0, SIZE);
state[0] = SIGMA[0];
state[1] = SIGMA[1];
state[2] = SIGMA[2];
state[3] = SIGMA[3];
Lend.Pack32(key, 0, state, 4, 8);
Lend.Pack32(nonce, 0, state, 13, 3);
}
private void ProcessBuffer()
{
if (bufferLength == 0)
{
return;
}
if (bufferLength < BLOCK_SIZE)
{
buffer[bufferLength] = 1;
Array.Clear(buffer, bufferLength + 1, BLOCK_SIZE - bufferLength - 1);
}
ulong t0 = Lend.Pack32(buffer, 0);
ulong t1 = Lend.Pack32(buffer, 4);
ulong t2 = Lend.Pack32(buffer, 8);
ulong t3 = Lend.Pack32(buffer, 12);
h0 += (uint)(t0 & 0x3ffffffU);
h1 += (uint)((((t1 << 32) | t0) >> 26) & 0x3ffffff);
h2 += (uint)((((t2 << 32) | t1) >> 20) & 0x3ffffff);
h3 += (uint)((((t3 << 32) | t2) >> 14) & 0x3ffffff);
h4 += (uint)(t3 >> 8);
if (bufferLength == BLOCK_SIZE)
{
h4 += (1 << 24);
}
ulong tp0 = mul32x32_64(h0, r0) + mul32x32_64(h1, s4) + mul32x32_64(h2, s3) + mul32x32_64(h3, s2) + mul32x32_64(h4, s1);
ulong tp1 = mul32x32_64(h0, r1) + mul32x32_64(h1, r0) + mul32x32_64(h2, s4) + mul32x32_64(h3, s3) + mul32x32_64(h4, s2);
ulong tp2 = mul32x32_64(h0, r2) + mul32x32_64(h1, r1) + mul32x32_64(h2, r0) + mul32x32_64(h3, s4) + mul32x32_64(h4, s3);
ulong tp3 = mul32x32_64(h0, r3) + mul32x32_64(h1, r2) + mul32x32_64(h2, r1) + mul32x32_64(h3, r0) + mul32x32_64(h4, s4);
ulong tp4 = mul32x32_64(h0, r4) + mul32x32_64(h1, r3) + mul32x32_64(h2, r2) + mul32x32_64(h3, r1) + mul32x32_64(h4, r0);
h0 = (uint)tp0 & 0x3ffffff; tp1 += (tp0 >> 26);
h1 = (uint)tp1 & 0x3ffffff; tp2 += (tp1 >> 26);
h2 = (uint)tp2 & 0x3ffffff; tp3 += (tp2 >> 26);
h3 = (uint)tp3 & 0x3ffffff; tp4 += (tp3 >> 26);
h4 = (uint)tp4 & 0x3ffffff;
h0 += (uint)(tp4 >> 26) * 5;
h1 += (h0 >> 26); h0 &= 0x3ffffff;
bufferLength = 0;
}
