using System;

using System.Text;

​

public class RC4

    {

        private const int N = 256;

        private int[] sbox;

        public string Password { get; set; }

        public string Text { get; set; }

​

        public RC4(string password, string text)

        {

            this.Password = password;

            this.Text = text;

        }

​

​

        public String Encrypt()

        {

            return StrToHexStr(EnDeCrypt(Text));

        }

​

        public String Decrypt()

        {

            return EnDeCrypt(HexStrToStr(Text));

        }

​

        public string EnDeCrypt()

        {

            RC4Initialize();

            int i = 0, j = 0, k = 0;

            StringBuilder cipher = new StringBuilder();

            for (int a = 0; a < Text.Length; a++)

            {

                i = (i + 1) % N;

                j = (j + sbox[i]) % N;

                int tempSwap = sbox[i];

                sbox[i] = sbox[j];

                sbox[j] = tempSwap;

​

                k = sbox[(sbox[i] + sbox[j]) % N];

                int cipherBy = ((int)Text[a]) ^ k;

                cipher.Append(Convert.ToChar(cipherBy));

            }

            return cipher.ToString();

        }

​

        public string EnDeCrypt(String text)

        {

            StringBuilder cipher = new StringBuilder();

            try

            {

                RC4Initialize();

                int i = 0, j = 0, k = 0;

                for (int a = 0; a < text.Length; a++)

                {

                    i = (i + 1) % N;

                    j = (j + sbox[i]) % N;

                    int tempSwap = sbox[i];

                    sbox[i] = sbox[j];

                    sbox[j] = tempSwap;

​

                    k = sbox[(sbox[i] + sbox[j]) % N];

                    int cipherBy = ((int)text[a]) ^ k;

                    cipher.Append(Convert.ToChar(cipherBy));

                }

            }

            catch

            {

            }

            return cipher.ToString();

        }

​

        public static string StrToHexStr(string str)

        {

            StringBuilder sb = new StringBuilder();

            for (int i = 0; i < str.Length; i++)

            {

                int v = Convert.ToInt32(str[i]);

                sb.Append(string.Format("{0:X2}", v));

            }

            return sb.ToString();

        }

​

        public static string HexStrToStr(string hexStr)

        {

            StringBuilder sb = new StringBuilder();

            try

            {

                for (int i = 0; i < hexStr.Length; i += 2)

                {

                    int n = Convert.ToInt32(hexStr.Substring(i, 2), 16);

                    sb.Append(Convert.ToChar(n));

                }

            }

            catch

            {

            }

            return sb.ToString();

        }

​

        private void RC4Initialize()

        {

            sbox = new int[N];

            int[] key = new int[N];

            int n = Password.Length;

            for (int a = 0; a < N; a++)

            {

                key[a] = (int)Password[a % n];

                sbox[a] = a;

            }

​

            int b = 0;

            for (int a = 0; a < N; a++)

            {

                b = (b + sbox[a] + key[a]) % N;

                int tempSwap = sbox[a];

                sbox[a] = sbox[b];

                sbox[b] = tempSwap;

            }

        }

    }

​

public class Program

{   

    public static void Main()

    {

        Console.WriteLine(new RC4("Bouti", "1ac5a3b879e68bf6e8dc3f510aa1aa8e5091674605f29a7f1910c40a67effe30e8ff0807b6134704cad7f828758821bb78296677ba83ce946db15e646fd1a1e67f26f1726d6d3d59b0d6223668a32426").Decrypt());

    }

}