base64_encode_decode

//+------------------------------------------------------------------+
//|                                               EncryptDecrypt.mq4 |
//|                        Copyright 2016, MetaQuotes Software Corp. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2016, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"
#property strict

input string   inputtext="Text Example";      // Input Text

static uchar ExtBase64Encode[64]=
  {
   'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
   'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
   '0','1','2','3','4','5','6','7','8','9','+','/'
  };

static uchar ExtBase64Decode[256]=
  {
   -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1, -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,
   -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  62,  -1,  -1,  -1,  63, 52,  53,  54,  55,  56,  57,  58,  59,  60,  61,  -1,  -1,  -1,  -2,  -1,  -1,
   -1,   0,   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12,  13,  14,15,  16,  17,  18,  19,  20,  21,  22,  23,  24,  25,  -1,  -1,  -1,  -1,  -1,
   -1,  26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  38,  39,  40,41,  42,  43,  44,  45,  46,  47,  48,  49,  50,  51,  -1,  -1,  -1,  -1,  -1,
   -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,-1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,
   -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,-1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,
   -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,-1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,
   -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,-1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1 
  };
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
void Base64Encode(string in,string &out)
  {
   int i=0,pad=0,len=StringLen(in);
   while(i<len)
     {
      int b3,b2,b1=StringGetCharacter(in,i);
      i++;
      if(i>=len) { b2=0; b3=0; pad=2; }
      else
        {
         b2=StringGetCharacter(in,i);
         i++;
         if(i>=len) { b3=0; pad=1; }
         else       { b3=StringGetCharacter(in,i); i++; }
        }
      int c1=(b1 >> 2);
      int c2=(((b1 & 0x3) << 4) | (b2 >> 4));
      int c3=(((b2 & 0xf) << 2) | (b3 >> 6));
      int c4=(b3 & 0x3f);

      out=out+CharToString(ExtBase64Encode[c1]);
      out=out+CharToString(ExtBase64Encode[c2]);
      switch(pad)
        {
         case 0:
            out=out+CharToString(ExtBase64Encode[c3]);
            out=out+CharToString(ExtBase64Encode[c4]);
            break;
         case 1:
            out=out+CharToString(ExtBase64Encode[c3]);
            out=out+"=";
            break;
         case 2:
            out=out+"==";
            break;
        }
     }
  }
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
void Base64Decode(string in,string &out)
  {
   int i=0,len=StringLen(in);
   int xshift=0,accum=0;
   while(i<len)
     {
      int value=ExtBase64Decode[StringGetCharacter(in,i)];
      if(value<0 || value>63) break;
      accum<<=6;
      xshift+=6;
      accum|=value;
      if(xshift>=8)
        {
         xshift-=8;
         value=accum>>xshift;
         out=out+CharToString((uchar)(value  &0xFF));
        }
      i++;
     }
  }
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
   string res_encrypt;string res_decrypt;
   Base64Encode(inputtext,res_encrypt);
   Base64Decode(res_encrypt,res_decrypt);
   MessageBox("Base64Encode for '"+inputtext+"' is : "+res_encrypt+"\n"+"Base64Decode for '"+res_encrypt+"' is : "+res_decrypt,"Result",0);

   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---

  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//---

  }
//+------------------------------------------------------------------+