YA: Masked Data 20130603212216AA1IFFJ

<?php
// http://answers.yahoo.com/question/answer?qid=20130603212216AA1IFFJ


// Obviously you can make the key anything you want.
defined('THE_KEY')? null : define('THE_KEY', 'jake whitton' );
defined('AUTHORIZED')? null : define('AUTHORIZED', (strpos(strtolower($_SERVER['HTTP_USER_AGENT']), THE_KEY) !== false) );


/***   Authenticate   ***/
if( !AUTHORIZED ){
    echo 'pageok';
    exit;
}

echo '<h2>Welcome Jake</h2>';

echo '<p>These contents can only be viewed by anyone with the knowledge of the key.</p>';