Кодирование текста

void __fastcall TForm1::Button1Click(TObject *Sender)\\кнопка зашифровать
{
  int key=CSpinEdit1->Text.ToInt()*-1,sz;
  TFileStream *file = new TFileStream(Edit1->Text,fmOpenRead);
  sz=file->Size;
  ProgressBar1->Max=sz;
  byte *b = new byte[sz];
  file->Read(b,sz);
  delete file;
  for (unsigned int i=0;i<sz;i+=abs(key))
  {
    b[i]+=key;
    ProgressBar1->Position=i;
  }
  file = new TFileStream(Edit2->Text,fmOpenWrite|fmCreate);
  file->Write(b,sz);
  delete file;
  delete b;
  ProgressBar1->Position=0;
}
void __fastcall TForm1::Button2Click(TObject *Sender)//кнопка расшифровать
{
  int key=CSpinEdit1->Text.ToInt(),sz;
  TFileStream *file = new TFileStream(Edit1->Text,fmOpenRead);
  sz=file->Size;
  ProgressBar1->Max=sz;
  byte *b = new byte[sz];
  file->Read(b,sz);
  delete file;
  for (unsigned int i=0;i<sz;i+=abs(key))
  {
    b[i]+=key;
    ProgressBar1->Position=i;
  }
  file = new TFileStream(Edit2->Text,fmOpenWrite|fmCreate);
  file->Write(b,sz);
  delete file;
  delete b;
  ProgressBar1->Position=0;
}

unsigned int index = (unsigned int)((unsigned char)(buf[i]))

#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//ФУНКЦИЯ ШИФРОВАНИЯ/ДЕШИФРОВАНИЯ
AnsiString XOR_Crypt(AnsiString in, AnsiString pass)
{
AnsiString out;
for (int x=1;x<in.Length()+1;x++)
        {
        out += (char)(in[x] ^ pass[x%pass.Length()+1]);
        }
return out;
}
//НАЧАЛО ПРОГРАММЫ
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
 
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
Edit1->Text = XOR_Crypt(Edit2->Text,"!");
}

char text[1] = "a", code[1];
code[0] = char(int(text[0])+1);