#!/usr/bin/perl
use IO::Socket;
my $welcome_msg = <<"EOT";
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 _    _  95   _________   ______   ______  _    _  _____  ______   ______ 
\\ \\  / /     | | | | | \\ | |  | | | |     | |  | |  | |  | |  \\ \\ | |     
 >|--|<      | | | | | | | |__| | | |     | |--| |  | |  | |  | | | |---- 
/_/  \\_\\     |_| |_| |_| |_|  |_| |_|____ |_|  |_| _|_|_ |_|  |_| |_|____ 

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

EOT

$|=1;
$lis = IO::Socket::INET->new (LocalPort => 3002, 
								Type => SOCK_STREAM, 
								Reuse=> 1, 
								Listen => 1000) or die "Error #1 $@\n";


sub x0 {
		my ($str, $key) = @_;
		my $enc_str = '';
		for my $char (split //, $str){
			my $decode = chop $key;
			$enc_str .= chr(ord($char) ^ ord($decode));
			$key = $decode . $key;
		}
		$enc_str =~ s/(.)/sprintf("%x",ord($1))/eg;
		return $enc_str;
}
while($c = $lis->accept()){
	if($pid=fork){
		next;
	}else{
		unless (defined $pid) {die "Threads problem $! \n";}
		$flag="";
		print $c $welcome_msg."\n\n";
		$authenticated=0;
		$str2auth=int(rand(20));
		print $str2auth;
		$password = <$c>;
		chomp($password);
		if($password eq $str2auth){
			$authenticated=1;
			print $c "\nPassword : \n";
			$str=<$c>;
			chomp($str);			
			$str=~s/X/XX/g;
			$encoded = x0($str,$str2auth);
			$encoded =~ tr/!-~/P-~!-O/;
			my $dd="";
			for($i=0;$i<=length($encoded);$i++){
				$dd.=hex(ord(substr($encoded,$i,1))+$str2auth);
			}
			for($i=0;$i<=$str2auth;$i++){
				$pos=hex(chr(ord(substr($encoded,$i,1)+$str2auth)));
				$dd=~s/2/$pos/g;
			}
			if(substr($dd,25,5).substr($dd,35,5).substr($dd,45,5).substr($dd,52,20).substr($dd,80,20) eq '7887487897986588789686597878864878865859865898659687897'){
				print $c $flag."\r\n";
			} 
		}
		close $c;
		exit;
   } 
   exit;
}
close $lis;