<!doctype html>
<html>
<head>
    <title>Demo</title>
</head>
<body>
    <ol>
        <?php
        require_once 'loader.php';
        Loader::register('../lib','RobThree\\Auth');

        use \RobThree\Auth\TwoFactorAuth;

        $tfa = new TwoFactorAuth('MyApp');

        echo '<li>First create a secret and associate it with a user';
        $secret = $tfa->createSecret(160);  // Though the default is an 80 bits secret (for backwards compatibility reasons) we recommend creating 160+ bits secrets (see RFC 4226 - Algorithm Requirements)
        echo '<li>Next create a QR code and let the user scan it:<br><img src="' . $tfa->getQRCodeImageAsDataUri('My label', $secret) . '"><br>...or display the secret to the user for manual entry: ' . chunk_split($secret, 4, ' ');
        $code = $tfa->getCode($secret);
        echo '<li>Next, have the user verify the code; at this time the code displayed by a 2FA-app would be: <span style="color:#00c">' . $code . '</span> (but that changes periodically)';
        echo '<li>When the code checks out, 2FA can be / is enabled; store (encrypted?) secret with user and have the user verify a code each time a new session is started.';
        echo '<li>When aforementioned code (' . $code . ') was entered, the result would be: ' . (($tfa->verifyCode($secret, $code) === true) ? '<span style="color:#0c0">OK</span>' : '<span style="color:#c00">FAIL</span>');
        ?>
    </ol>
    <p>Note: Make sure your server-time is <a href="http://en.wikipedia.org/wiki/Network_Time_Protocol">NTP-synced</a>! Depending on the $discrepancy allowed your time cannot drift too much from the users' time!</p>
    <?php
    try {
        $tfa->ensureCorrectTime();
        echo 'Your hosts time seems to be correct / within margin';
    } catch (RobThree\Auth\TwoFactorAuthException $ex) {
        echo '<b>Warning:</b> Your hosts time seems to be off: ' . $ex->getMessage();
    }
    ?>
</body>
</html>