A very basic Json Web Token (JWT) implementation that handles the expiration registered claim "exp".
include("MicroJWT.php");
$microJwt = new MicroJWT("adamngoodsecret", "HS256");
$data = array("username"=>"johndoe"); // An array of datas
$expiration = 24 * 60 * 60; // Expiration set for 24h
$token = $microJwt->encode($data, $expiration);
echo($token);
echo'<br/>';
$decoded = $microJwt->decode($token);
var_dump($decoded);
echo'<br/>';