What security measures should be implemented to restrict access to the iFrame browser and ensure that only authorized users can use it?

To restrict access to the iFrame browser and ensure only authorized users can use it, you can implement security measures such as user authentication, session management, and IP address filtering. By requiring users to log in with valid credentials and storing their session information securely, you can control access to the iFrame browser. Additionally, you can restrict access based on the user's IP address to further enhance security.

// Check if user is logged in
session_start();
if (!isset($_SESSION['logged_in']) || $_SESSION['logged_in'] !== true) {
    header("Location: login.php");
    exit();
}

// Check if user's IP address is authorized
$allowed_ips = ['192.168.1.1', '10.0.0.1']; // Add authorized IP addresses here
if (!in_array($_SERVER['REMOTE_ADDR'], $allowed_ips)) {
    die("Unauthorized access");
}