#!/usr/local/bin/perl
#
# $Id: dec7.pl,v 1.2 2006/08/31 08:53:58 sjc Exp $

use strict;

#my @xlat = ( 0x64, 0x73, 0x66, 0x64, 0x3b, 0x6b, 0x66, 0x6f, 0x41,
#          0x2c, 0x2e, 0x69, 0x79, 0x65, 0x77, 0x72, 0x6b, 0x6c,
#          0x64, 0x4a, 0x4b, 0x44, 0x48, 0x53 , 0x55, 0x42 );

# xor string is: dsfd;kfoA,.iyewrkldJKDHSUBs
my @xlat        = (0x64, 0x73, 0x66, 0x64, 0x3b, 0x6b, 0x66, 0x6f, # offset 0 - 7
		0x41, 0x2c, 0x2e, 0x69, 0x79, 0x65, 0x77, 0x72, # offset 8 - F
		0x6b, 0x6c, 0x64, 0x4a, 0x4b, 0x44, 0x48, 0x53,
		0x55, 0x42, # this is the end of the string as published
		0x73 # this has been added
		);

my $pass = $ARGV[0];

die "Usage: $0 <cisco 7 passwd>\n" if $pass eq "";

$pass = &backpass($pass);	# sub to convert var to be usable!

print $pass."\n";


sub backpass {

	my ($backpass) = shift (@_);

	my ($s, $e) = ($backpass =~ /^(..)(.+)/o);
	my $dp;
	for (my $i = 0; $i < length($e); $i+=2) {
		$dp .= sprintf "%c",hex(substr($e,$i,2))^$xlat[$s++];
	}
	return $dp;
}