Preventing Cross site request forgery in PHP

CSRF.php

<?PHP
session_start();
//Include this PHP file for generating random strings: https://github.com/IcyApril/CryptoLib/blob/master/src/CryptoLib.php
require 'CryptoLib.php';

//Generate a form token that we'll use to authenticate that this was a form we created
if(!isset($_SESSION['FormAuthenticatorToken']))
{
  $_SESSION['FormAuthenticatorToken'] = IcyApril\CryptoLib::randomString(50);
}

/*Form submission handler*/
if(isset($_POST['FormAuthenticatorToken']))
{
  if($_POST['FormAuthenticatorToken'] !== $_SESSION['FormAuthenticatorToken'])
  {
    echo 'You submitted a form that was not from this site';
  }
  else
  {
    //process the form
  }
}
?>

<form action="#" method="POST">
  <input type="hidden" name="FormAuthenticatorToken" value="<?= $_SESSION['FormAuthenticatorToken'] ?>" />
  Name:<input type="text" name="Name"/><br/>
  Email:<input type="text" name="Email"/><br/>
  <input type="submit"/>
</form>