private BigInteger GetValueY(BigInteger x)
{
BigInteger value = GetYSquare(x);
BigInteger y = BigIntigerMath.SqrtModEuler(value, modulo);
return(y);
}
private Point MultipySamePoints()
{
BigInteger x1 = pointP.x;
BigInteger y1 = pointP.y;
BigInteger x2 = pointQ.x;
BigInteger y2 = pointQ.y;
BigInteger lambda = ((3 * BigInteger.ModPow(x1, 2, modulo) + a) * BigIntigerMath.InverseNumberMod(2 * y1, modulo)) % modulo;
BigInteger x3 = (BigInteger.ModPow(lambda, 2, modulo) - 2 * x1) % modulo;
BigInteger y3 = (lambda * (x1 - x3) - y1) % modulo;
return(new Point(x3, y3));
}
private Point AddDifferentPointsPAndQ()
{
BigInteger x1 = pointP.x;
BigInteger y1 = pointP.y;
BigInteger x2 = pointQ.x;
BigInteger y2 = pointQ.y;
BigInteger lambda = ((y2 - y1) * BigIntigerMath.InverseNumberMod(x2 - x1, modulo)) % modulo;
BigInteger x3 = (BigInteger.ModPow(lambda, 2, modulo) - x1 - x2) % modulo;
BigInteger y3 = (lambda * (x1 - x3) - y1) % modulo;
return(new Point(x3, y3));
}
public Point EncryptMessage(string massage, BigInteger ni)
{
byte[] bytes = System.Text.Encoding.UTF8.GetBytes(massage);
BigInteger M = new BigInteger(bytes);
for (int i = 1; i <= ni; i++)
{
BigInteger x = (M * ni + i) % modulo;
BigInteger ySquare = (BigInteger.ModPow(x, 3, modulo) + x * A + B) % modulo;
if (SquareRest.IsSquareRest(modulo, ySquare))
{
BigInteger y = BigIntigerMath.SqrtModEuler(ySquare, modulo);
return(new Point(x, y));
}
}
return(new Point(-1));
}