private static PointExt PointCopy(PointExt p)
{
PointExt r = new PointExt();
X448Field.Copy(p.x, 0, r.x, 0);
X448Field.Copy(p.y, 0, r.y, 0);
X448Field.Copy(p.z, 0, r.z, 0);
return(r);
}
internal static void ScalarMultBaseXY(byte[] k, int kOff, uint[] x, uint[] y)
{
byte[] n = new byte[ScalarBytes];
PruneScalar(k, kOff, n);
PointExt p = new PointExt();
ScalarMultBase(n, p);
X448Field.Copy(p.x, 0, x, 0);
X448Field.Copy(p.y, 0, y, 0);
}
internal static void ScalarMultBaseXY(byte[] k, int kOff, uint[] x, uint[] y)
{
byte[] n = new byte[ScalarBytes];
PruneScalar(k, kOff, n);
PointExt p = new PointExt();
ScalarMultBase(n, p);
if (0 == CheckPoint(p.x, p.y, p.z))
{
throw new InvalidOperationException();
}
X448Field.Copy(p.x, 0, x, 0);
X448Field.Copy(p.y, 0, y, 0);
}
public static void Precompute()
{
lock (precompLock)
{
if (precompBase != null)
{
return;
}
PointExt p = new PointExt();
X448Field.Copy(B_x, 0, p.x, 0);
X448Field.Copy(B_y, 0, p.y, 0);
PointExtendXY(p);
precompBaseTable = PointPrecompVar(p, 1 << (WnafWidthBase - 2));
precompBase = new uint[PrecompBlocks * PrecompPoints * 2 * X448Field.Size];
int off = 0;
for (int b = 0; b < PrecompBlocks; ++b)
{
PointExt[] ds = new PointExt[PrecompTeeth];
PointExt sum = new PointExt();
PointSetNeutral(sum);
for (int t = 0; t < PrecompTeeth; ++t)
{
PointAddVar(true, p, sum);
PointDouble(p);
ds[t] = PointCopy(p);
if (b + t != PrecompBlocks + PrecompTeeth - 2)
{
for (int s = 1; s < PrecompSpacing; ++s)
{
PointDouble(p);
}
}
}
PointExt[] points = new PointExt[PrecompPoints];
int k = 0;
points[k++] = sum;
for (int t = 0; t < (PrecompTeeth - 1); ++t)
{
int size = 1 << t;
for (int j = 0; j < size; ++j, ++k)
{
points[k] = PointCopy(points[k - size]);
PointAddVar(false, ds[t], points[k]);
}
}
Debug.Assert(k == PrecompPoints);
for (int i = 0; i < PrecompPoints; ++i)
{
PointExt q = points[i];
// TODO[ed448] Batch inversion
X448Field.Inv(q.z, q.z);
X448Field.Mul(q.x, q.z, q.x);
X448Field.Mul(q.y, q.z, q.y);
//X448Field.Normalize(q.x);
//X448Field.Normalize(q.y);
X448Field.Copy(q.x, 0, precompBase, off); off += X448Field.Size;
X448Field.Copy(q.y, 0, precompBase, off); off += X448Field.Size;
}
}
Debug.Assert(off == precompBase.Length);
}
}
