Encrypting using password and xor operator

This file en/decryption system only use one and same function. For encryption call it once and for decryption once again. You can enter a own password with no limmit of characters (always remember). For deeper encryption try using signs like "*%�§&#...". The system based on the xor operant, same like "~~", I must use it in this way coz my editor don't accept the command xor! It's very recommend to work with text, gfx and files wich never should change by others!

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    Remstart
   ------------------------------------------------------------------
   Author:        Volker Stepprath of Testaware
   Project:       Password Encryption System
   Version:       0.00.001 ;D
   Language:      DarkBASIC Professional v1.057
   Description:   File en/decrypt using password and xor operator
   Date:          10. November 2004
   ------------------------------------------------------------------
   Hint 1:        Call function first as encrypt and twice to decrypt
   Hint 2:        Use function as include in your own sources
   Hint 3:        For deep encryption use characters like "%&!#*?..."
   ------------------------------------------------------------------
Remend

xFileName$="Atomix 2004.exe"        : Rem * Name of the file to en/decrypt
xPassWord$="DarkBASIC Professional" : Rem * Password (try your own characters)

_EncryptFile(xFileName$,xPassWord$) : Rem * Call function to en/decrypt file

FUNCTION _EncryptFile(xFileName$,xPassWord$)

   open to read 1,xFileName$
   make memblock from file 1,1
   close file 1

   xFileSize=get memblock size(1)-1
   xPassSize=len(xPassWord$)

   for a=0 to xFileSize
      b=memblock byte(1,a)
      if b<>0
         inc c : if c>xPassSize then c=1
         b=b ~~ asc(mid$(xPassWord$,c))
         if b<>0 then write memblock byte 1,a,b
      endif
   next a

   delete file xFileName$

   open to write 1,xFileName$
   for a=0 to xFileSize
      write byte 1,memblock byte(1,a)
   next a
   close file 1

   delete memblock 1

ENDFUNCTION