check_ajax_referer( int|string $action = -1, false|string $query_arg = false, bool $stop = true )

function check_ajax_referer( $action = -1, $query_arg = false, $die = true ) {
	if ( -1 == $action ) {
		_doing_it_wrong( __FUNCTION__, __( 'You should specify a nonce action to be verified by using the first parameter.' ), 'WP-4.7' );
	}

	$nonce = '';

	if ( $query_arg && isset( $_REQUEST[ $query_arg ] ) )
		$nonce = $_REQUEST[ $query_arg ];
	elseif ( isset( $_REQUEST['_ajax_nonce'] ) )
		$nonce = $_REQUEST['_ajax_nonce'];
	elseif ( isset( $_REQUEST['_wpnonce'] ) )
		$nonce = $_REQUEST['_wpnonce'];

	$result = wp_verify_nonce( $nonce, $action );

	/**
	 * Fires once the Ajax request has been validated or not.
	 *
	 * @since WP-2.1.0
	 *
	 * @param string    $action The Ajax nonce action.
	 * @param false|int $result False if the nonce is invalid, 1 if the nonce is valid and generated between
	 *                          0-12 hours ago, 2 if the nonce is valid and generated between 12-24 hours ago.
	 */
	do_action( 'check_ajax_referer', $action, $result );

	if ( $die && false === $result ) {
		if ( wp_doing_ajax() ) {
			wp_die( -1, 403 );
		} else {
			die( '-1' );
		}
	}

	return $result;
}