Using nonces in WordPress plugin

secure-plugin.php

<?php

add_action('wp_enqueue_scripts', 'load_my_plugin_script');

function load_my_plugin_script() {
	// Register the script with all details and ensures it is loaded after jQuery
	wp_register_script('secure-plugin', plugin_dir_url( __FILE__ ). 'js/secure-plugin.js', array( 'jquery' ) );

	// Here happens the magic, we add some details to an object that we can later reference and read from in our JS code.
	wp_localize_script(
		'secure-plugin',
		'plugin_ajax_object',
		array(
			'nonce'  => wp_create_nonce('secure-plugin-nonce')
		)
	);
	// Once that is done, we can now enqueue the script
	wp_enqueue_script('secure-plugin');
}