如何通过加密cookie来保护我在api中的api

Question

I have a question is it possible to encrypt the cookies for my api in php?

i have this code to be not used directly or they need account to able to use my api

include('../../info.php'); // here is the code for session
      if(!isset($_SESSION['user'])){ // user is the user_type in my db
      header("HTTP/1.1 401");
readfile('../../error/401.html');
exit();
  }
    if ( $_SERVER['REQUEST_METHOD']=='GET' && realpath(__FILE__) == realpath( $_SERVER['SCRIPT_FILENAME'] ) ) {
        http_response_code(401);
        header( 'HTTP/1.0 401 Forbidden', TRUE, 401 );
        die( readfile('../../error/401.html') );

    }

but when i try POSTMAN with my cookies it still give me the response of the api instead of getting the response code 401 but if i disable cookies in POSTMAN i get 401.

How do i secure my api?