using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
using System.Security.Cryptography;
using System.IO;
using System.ComponentModel;
using Microsoft.VisualBasic;


namespace Helper
{
    public class Encrytp
    {
        public String GBPassword = ConfigurationManager.AppSettings["GBPassword"].ToString();
        public String LOGeneraKey = ConfigurationManager.AppSettings["LOGeneraKey"].ToString();

        /// <summary>
        /// 
        /// </summary>
        /// <param name="InputString"></param>
        /// <param name="SecretKey"></param>
        /// <param name="CyphMode"></param>
        /// <returns></returns>
        public String DecryptString(String InputString, CipherMode CyphMode = CipherMode.ECB)
        {

            String SecretKey = LOGeneraKey;

            if (InputString == string.Empty)
            {
                return "";
            }
            else
            {
                TripleDESCryptoServiceProvider Des = new TripleDESCryptoServiceProvider();
                byte[] InputbyteArray = new byte[Convert.ToInt32(InputString.Length / 2 - 1) + 1];
                MD5CryptoServiceProvider hashMD5 = new MD5CryptoServiceProvider();

                Des.Key = hashMD5.ComputeHash(ASCIIEncoding.ASCII.GetBytes(SecretKey));
                Des.Mode = CyphMode;
                //Put the input string into the byte array
                int X = 0;

                for (X = 0; X <= InputbyteArray.Length - 1; X++)
                {
                    Int32 IJ = (Convert.ToInt32(InputString.Substring(X * 2, 2), 16));
                    ByteConverter BT = new ByteConverter();
                    InputbyteArray[X] = new byte();
                    InputbyteArray[X] = Convert.ToByte(BT.ConvertTo(IJ, typeof(byte)));
                }

                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, Des.CreateDecryptor(), CryptoStreamMode.Write);

                //Flush the data through the crypto stream into the memory stream
                cs.Write(InputbyteArray, 0, InputbyteArray.Length);
                cs.FlushFinalBlock();

                ////Get the decrypted data back from the memory stream
                StringBuilder ret = new StringBuilder();
                byte[] B = ms.ToArray();

                ms.Close();

                int I = 0;

                for (I = 0; I <= Information.UBound(B); I++)
                {
                    ret.Append(Strings.Chr(B[I]));
                }

                return ret.ToString();
            }
        }
    }
}