Eroor C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Globalization;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        public static bool metoda0(string string_0, string string_1, string string_2)
        {
            return smethod_1(0x7a5e26ed, 0x51abecb1, string_2, string_0, string_1, string.Empty);
        }
        internal static bool smethod_1(uint uint_0, uint uint_1, string string_0, string string_1, string string_2, string string_3)
        {
            if (string.IsNullOrEmpty(string_0))
            {
                return false;
            }
            if (string_0.Length != 0x20)
            {
                return false;
            }
            if (((uint_0 == 0) || (uint_1 == 0)) || (uint_0 == uint_1))
            {
                return false;
            }
            bool flag2 = false;
            string str = metoda2(string_0);
            if (string.IsNullOrEmpty(str))
            {
                return false;
            }
            string str2 = metoda5(metoda4(str, string_2, string_3), uint_0, uint_1);
            if (string.IsNullOrEmpty(string_1))
            {
                string_1 = "";
            }
            StringBuilder builder = new StringBuilder();
            char ch = (char)((byte)(((uint_0 + uint_1) % 0x1a) + 0x41));
            builder.Append(ch);
            builder.Append(metoda3(string_1.ToUpper(), uint_0, uint_1));
            if (!string.IsNullOrEmpty(str2) && (str2[0] == '\0'))
            {
                flag2 = true;
                if (0x57 != (str2[2] ^ ((byte)uint_1)))
                {
                    flag2 = false;
                }
                if (0x53 != (str2[5] ^ ((byte)uint_1)))
                {
                    flag2 = false;
                }
                if (0x52 != (str2[7] ^ ((byte)uint_1)))
                {
                    flag2 = false;
                }
                if (0x44 != (str2[10] ^ ((byte)uint_1)))
                {
                    flag2 = false;
                }
                if (0x57 != ((str2[11] ^ 'S') ^ ((byte)uint_0)))
                {
                    flag2 = false;
                }
                return flag2;
            }
            return (string.Compare(builder.ToString(), str2, false) == 0);
        }


        private static string metoda2(string string_0)
        {
            if (string.IsNullOrEmpty(string_0) || ((string_0.Length & 1) != 0))
            {
                return string.Empty;
            }
            int capacity = string_0.Length / 2;
            StringBuilder builder2 = new StringBuilder(capacity)
            {
                Length = capacity
            };
            for (int i = 0; i < capacity; i++)
            {
                int num3;
                if (!int.TryParse(string_0.Substring(i * 2, 2), NumberStyles.HexNumber, null, out num3))
                {
                    return string.Empty;
                }
                builder2[i] = (char)num3;
            }
            return builder2.ToString();
        }

        private static string metoda3(string string_0, uint uint_0, uint uint_1)
        {
            if (string.IsNullOrEmpty(string_0))
            {
                return string.Empty;
            }
            uint num = 0;
            int length = string_0.Length;
            for (int i = 0; i < length; i++)
            {
                num += (uint)((((string_0[i] * i) * (i + 1)) + string_0[i]) + i);
            }
            StringBuilder builder2 = new StringBuilder
            {
                Length = 12
            };
            for (int j = 0; j < 11; j++)
            {
                int num5 = (int)((((((10 - j) + 1) * uint_0) * uint_1) + num) % ((long)length));
                builder2[j] = (char)((byte)((((string_0[num5] + string_0[j % length]) + string_0[(int)((j * num) % ((long)length))]) + j) + num));
            }
            builder2[11] = '\0';
            return builder2.ToString();
        }

        private static string metoda4(string string_0, string string_1, string string_2)
        {
            StringBuilder builder = new StringBuilder();
            builder.Append(string_1.ToUpper());
            builder.Append(string_2.ToUpper());
            if (builder.Length <= 0)
            {
                return string_0;
            }
            string str2 = metoda3(builder.ToString(), 0, 0);
            StringBuilder builder3 = new StringBuilder(0x10)
            {
                Length = 0x10
            };
            for (int i = 0; i < 0x10; i++)
            {
                builder3[i] = (char)((byte)(string_0[i] ^ str2[i % 12]));
            }
            return builder3.ToString();
        }
        private static string metoda5(string string_0, uint uint_0, uint uint_1)
        {
            StringBuilder builder = new StringBuilder((string_0.Length / 4) * 3);
            for (int i = 0; i < string_0.Length; i += 4)
            {
                builder.Append(metoda_finala(string_0.Substring(i, 4), uint_0, uint_1));
            }
            return builder.ToString();
        }

        private static uint metoda6(uint uint_0, uint uint_1, uint uint_2)
        {
            ulong num = uint_0;
            uint num2 = 1;
            for (uint i = 0; i < 0x20; i++)
            {
                if ((uint_2 & 1) != 0)
                {
                    num2 = (uint)((num2 * num) % ((ulong)uint_1));
                }
                num = (num * num) % ((ulong)uint_1);
                uint_2 = uint_2 >> 1;
            }
            return num2;
        }

        private static string metoda_finala(string string_0, uint uint_0, uint uint_1)
        {

            uint num = ((string_0[0] | (string_0[1] << 8)) | (string_0[2] << 0x10)) | (string_0[3] << 0x18);
            uint num2 = metoda6(num, uint_0, uint_1);
            StringBuilder builder = new StringBuilder(3)
            {
                Length = 3
            };
            builder[0] = (char)(num2 & 0xff);
            builder[1] = (char)((ushort)((num2 & 0xff00) >> 8));
            builder[2] = (char)((ushort)((num2 & 0xff0000) >> 0x10));
            return builder.ToString();
        }



        private void Form1_Load(object sender, EventArgs e)
        {

        }



    }
}