public bool SingVer(byte[] H, string sing, EllipticCurve_Point Q)
{
int midl = Maths.Length(this.curv.N) / 4;
string Rvector = sing.Substring(0, midl);
string Svector = sing.Substring(midl, midl);
BigInteger r = BigInteger.Parse(SupportEDS.DecStringFromHexString(Rvector));
BigInteger s = BigInteger.Parse(SupportEDS.DecStringFromHexString(Svector));
if ((r < 1) || (r > (this.curv.N - 1)) || (s < 1) || (s > (this.curv.N - 1)))
{
return(false);
}
BigInteger alpha = BigInteger.Parse(SupportEDS.DecStringFromByteArray(H));
BigInteger e = alpha % this.curv.N;
if (e == 0)
{
e = 1;
}
BigInteger v = Maths.GetInverse(e, this.curv.N);
BigInteger z1 = (s * v) % this.curv.N;
BigInteger z2 = this.curv.N + ((-(r * v)) % this.curv.N);
EllipticCurve_Point A = new EllipticCurve_Point();
EllipticCurve_Point B = new EllipticCurve_Point();
EllipticCurve_Point C = new EllipticCurve_Point();
curv.Mult(z1, this.curv.G, ref A);
curv.Mult(z2, Q, ref B);
curv.Sum(A, B, ref C);
BigInteger R = C.X % this.curv.N;
if (R == r)
{
return(true);
}
else
{
return(false);
}
}
public bool Sum(EllipticCurve_Point p1, EllipticCurve_Point p2, ref EllipticCurve_Point res)
{
BigInteger lambda = -1;
if (p1.IsNull && p2.IsNull)
{
res = EllipticCurve.O;
return(true);
}
BigInteger ps = (p - p2.Y) % p;
if (p1.X == p2.X && p1.Y == ps)
{
res = EllipticCurve.O;
return(true);
}
if (p1.IsNull)
{
res = new EllipticCurve_Point(p2);
return(true);
}
if (p2.IsNull)
{
res = new EllipticCurve_Point(p1);
return(true);
}
if (p1.X != p2.X)
{
BigInteger i = (p2.X - p1.X) % p;
BigInteger y = (p2.Y - p1.Y) % p;
if (i < 0)
{
i += p;
}
i = Maths.GetInverse(i, p);
if (i == 0)
{
return(false);
}
lambda = (i * y) % p;
}
else
{
BigInteger y2 = (2 * p1.Y) % p;
BigInteger i = Maths.GetInverse(y2, p);
if (i < 0)
{
i += p;
}
if (i == 0)
{
return(false);
}
BigInteger x3 = (3 * p1.X) % p;
x3 = (x3 * p1.X) % p;
x3 = (x3 + a) % p;
lambda = (x3 * i) % p;
}
res = new EllipticCurve_Point();
BigInteger lambda2 = (lambda * lambda) % p;
BigInteger delta1 = (p1.X + p2.X) % p;
res.X = (lambda2 - delta1) % p;
BigInteger delta2 = (p1.X - res.X) % p;
delta2 = (lambda * delta2) % p;
res.Y = (delta2 - p1.Y) % p;
if (res.X < 0)
{
res.X += p;
}
if (res.Y < 0)
{
res.Y += p;
}
return(true);
}
private void Recurse(BigInteger p, List <BigInteger> A, ref List <BigInteger> root)
{
int count = 0, degreeA = A.Count - 1, degreeB = 0;
BigInteger exp = 0, p1 = p - 1, D = 0, a = 0, b = 0, c = 0, e = 0;
List <BigInteger> B = null, d = null;
List <BigInteger> q = null, r = null, u = null;
exp = p1 / 2;
if (degreeA != 0)
{
if (degreeA == 1)
{
if (A[0] != 0)
{
a = Maths.GetInverse(A[1], p);
b = A[0];
b = -b;
b = Maths.MulMod(b, a, p);
root.Add(b);
}
}
else if (degreeA == 2)
{
a = Maths.MulMod(A[1], A[1], p);
b = Maths.MulMod(A[0], A[2], p);
c = Maths.MulMod(b, 4, p);
D = Maths.SubMod(a, c, p);
e = hcr.SquareRootModPrime(D, p);
BigInteger test = (e * e) % p;
if (e == 1)
{
return;
}
a = Maths.MulMod(A[2], 2, p);
D = Maths.GetInverse(a, p);
if (D == 0)
{
a = -a;
a = Maths.AddMod(a, p, p);
D = Maths.GetInverse(a, p);
}
a = Maths.SubMod(e, A[1], p);
root.Add(Maths.MulMod(a, D, p));
A[1] = -A[1];
e = -e;
a = Maths.AddMod(A[1], e, p);
root.Add(Maths.MulMod(a, D, p));
}
else
{
do
{
count++;
a = hcr.RandomRange(0, p1);
u = new List <BigInteger>();
u.Add(a);
u.Add(1);
PolyPowMod(p, exp, u, A, ref d);
if (d.Count - 1 != 0)
{
d[0] = Maths.SubMod(d[0], 1, p);
B = PolyGCDMod(p, d, A);
if (B.Count == 1 && B[0] == 1)
{
return;
}
degreeB = B.Count - 1;
}
}while (count < 16 && degreeB == 0 || degreeB == degreeA);
if (count == 16)
{
return;
}
Recurse(p, B, ref root);
PolyDivMod(p, A, B, ref q, ref r);
Recurse(p, q, ref root);
}
}
}
