function LamerzEncrypt(const Buffer; const BufSize:integer): longword;
asm
  mov ecx,eax; or eax,edx
  and eax,ecx; jz @@Stop
  push esi; push edi;
  mov esi,eax; mov edi,eax
  mov ecx,edx
@@Loop: lodsb; 
  xor eax,ecx; stosb
  dec ecx; jnz @@Loop
  pop edi; pop esi
@@Stop:
end;

procedure Enkripsi;
var
  Source, Dest: TFileStream;
  i: Integer;
  a, buff: Char;
begin
  Source:= TFileStream.Create('C:\file_awal.doc',fmOpenRead);
  Dest:= TFileStream.Create('C:\file_enkripsi.doc',fmCreate);
  for i:= 0 to Source.Size - 1 do
    begin
      Source.Read(buff, SIZEOF(buff));
      a:= Char(ord(buff) + 10); //ini rumusnya silahkan diganti
      Dest.Write(a, sizeof(a));
    end;
  Source.Free;
  Dest.Free;
end;