DetermineChar2Parameters() [2/2]

static void System.Security.Cryptography.EccKeyFormatHelper.DetermineChar2Parameters ( in ECParameters ecParameters, ref int m, ref int k1, ref int k2, ref int k3 )

inlinestaticprivate

Definition at line 327 of file EccKeyFormatHelper.cs.

    {
        byte[] polynomial = ecParameters.Curve.Polynomial;
        int num = polynomial.Length - 1;
        if (polynomial[0] == 0 || (polynomial[num] & 1) != 1)
        {
            throw new CryptographicException(System.SR.Cryptography_InvalidECCharacteristic2Curve);
        }
        for (int num2 = 7; num2 >= 0; num2--)
        {
            int num3 = 1 << num2;
            if ((polynomial[0] & num3) == num3)
            {
                m = checked(8 * num + num2);
            }
        }
        for (int i = 0; i < polynomial.Length; i++)
        {
            int num4 = num - i;
            byte b = polynomial[num4];
            for (int j = 0; j < 8; j++)
            {
                int num5 = 1 << j;
                if ((b & num5) != num5)
                {
                    continue;
                }
                int num6 = 8 * i + j;
                if (num6 == 0)
                {
                    continue;
                }
                if (num6 == m)
                {
                    break;
                }
                if (k1 < 0)
                {
                    k1 = num6;
                    continue;
                }
                if (k2 < 0)
                {
                    k2 = num6;
                    continue;
                }
                if (k3 < 0)
                {
                    k3 = num6;
                    continue;
                }
                throw new CryptographicException(System.SR.Cryptography_InvalidECCharacteristic2Curve);
            }
        }
        if (k3 <= 0)
        {
            if (k2 > 0)
            {
                throw new CryptographicException(System.SR.Cryptography_InvalidECCharacteristic2Curve);
            }
            if (k1 <= 0)
            {
                throw new CryptographicException(System.SR.Cryptography_InvalidECCharacteristic2Curve);
            }
        }
    }

References System.SR.Cryptography_InvalidECCharacteristic2Curve.