ascii-hex-crypt.php

<?php

dehexify("414D415A494E47");
hexify("If you can read this, you are not special. You just know ASCII.");

function dehexify($x) {
    $buf='';
    for ($i = 0; $i < strlen($x); $i++)
    {
        if ($x[$i] == ' ') {
            echo ' ';
            $buf = '';
        } else {
            $buf .= $x[$i];
            
            if (strlen($buf) == 2) {
                echo chr(hexdec($buf));
                $buf = '';
            }
        }
    }
    echo "\n";
}

function hexify($x)
{
    for ($i = 0; $i < strlen($x); $i++)
    {
        if ($x[$i] == ' ') { echo ' '; continue; }
        echo strtoupper(dechex(ord($x[$i])));
    }
    echo "\n";
}