<?php
// Algoritmos originales del desafío Contact para php-hispano.net
// No calificable
function codificar($cadena) {
        $cadena .= md5($cadena); $c2 = \'\';
        $array = array(\'00\'=>\'*\',\'01\'=>\'$\',\'10\'=>\'&\',\'11\'=>\'#\');
        for ($i = 0; $i < strlen($cadena); $i++) {
                $bin = str_pad(decbin(ord($cadena{$i})),8,\'0\',STR_PAD_LEFT);
                $c2 .= preg_replace(\'/([0-1]{2})/e\',\'$array[\\\'\\1\\\']\',$bin);
        }
        return str_replace(\'1\',\'\',preg_replace(\'/([\\$&#\\*]{4})(\\1+)?/e\',\'\\\'\\1\\\'.((strlen(\\\'\\2\\\')/4)+1)\',$c2));
}

function decodificar($cadena) {
        $array = array(\'*\'=>\'00\',\'$\'=>\'01\',\'&\'=>\'10\',\'#\'=>\'11\');
        $cadena = preg_replace(\'/([\\$\\#\\&\\*]{4})(?(1)([0-9]+))/e\',\'str_repeat(\\\'\\1\\\',\\2)\',$cadena);
        $cadena = preg_replace(\'/([\\$\\#\\&\\*])([\\$\\#\\&\\*])([\\$\\#\\&\\*])([\\$\\#\\&\\*])/e\',\'chr(bindec($array[\\\'\\1\\\'].$array[\\\'\\2\\\'].$ar
ray[\\\'\\3\\\'].$array[\\\'\\4\\\']))\',$cadena);
        $mensaje = substr($cadena,0,-32);       
        return md5($mensaje) == substr($cadena,-32) ? $mensaje : false;
}
?>