#!/usr/bin/perl
#
#  XOR FILE Encryption/Decryption
#
#  Copyright 2018 (c) Todor Donev <todor.donev at gmail.com>
#  https://ethical-hacker.org/
#  https://facebook.com/ethicalhackerorg
#
#  Disclaimer:
#  This or previous programs is for Educational
#  purpose ONLY. Do not use it without permission.
#  The usual disclaimer applies, especially the
#  fact that Todor Donev is not liable for any
#  damages caused by direct or indirect use of the
#  information or functionality provided by these
#  programs. The author or any Internet provider
#  bears NO responsibility for content or misuse
#  of these programs or any derivatives thereof.
#  By using these programs you accept the fact
#  that any damage (dataloss, system crash,
#  system compromise, etc.) caused by the use
#  of these programs is not Todor Donev's
#  responsibility.
#
#  Use them at your own risk!
#

use warnings;
use strict;

print "[ XOR FILE Encryption/Decryption\n";
print "[ ======\n";
print "[ Author: Todor Donev <todor.donev at gmail.com>\n";
print "[ https://ethical-hacker.org/\n";
print "[ https://fb.com/ethicalhackerorg\n";
print "[ ======\n";
die   "[ Usage: $0 <hex key> <input file> <output file>\n" if(@ARGV != 3);
my $key = chr(hex($ARGV[0]));
print "[ Opening $ARGV[1]\n";
open(IN, "<$ARGV[1]") or die "[ Error: Can't read $ARGV[1]: $!\n";
print "[ Error: $ARGV[1] is empty file\n" and exit if (-z $ARGV[1]);
open(OUT, ">$ARGV[2]") or die "[ Error: Can't wrote $ARGV[2]: $!\n";
binmode(IN); binmode(OUT);
print "[ Calculation..\n";
while( sysread(IN,my $in,length($key))) {
    print OUT $in^substr($key,0,length($in));
}
print "[ Ready and $ARGV[2] file is closed.\n";
close(IN);
close(OUT);