Block Spam attacks on wp registeration page.

ras.php

<?php
/*
Plugin Name: Registeration Anti-Spam
Plugin URI: https://gist.github.com/louy/6212415
Description: Block Spam attacks on wp registeration page.
Author: Louy Alakkad
Version: 1.0
Author URI: http://l0uy.com/
*/

function ras_get_field_name() {
	return wp_nonce_tick();
}

add_action( 'login_form_register', 'ras_login_form_register' );
function ras_login_form_register() {
	$field = ras_get_field_name();
	
	@$user_login = $_POST['user_login_'.$field];
	@$user_email = $_POST['user_email_'.$field];
	
	$_POST['user_login'] = $user_login;
	$_POST['user_email'] = $user_email;
	
	unset( $_POST['user_login_'.$field] );
	unset( $_POST['user_email_'.$field] );
	
	define( 'RAS_RUNNING', true );
	ob_start();
}

add_action('login_footer', 'ras_login_footer');
function ras_login_footer() {
	if( defined( 'RAS_RUNNING' ) && RAS_RUNNING ) {
		$output = ob_get_clean();
		
		$field = ras_get_field_name();
		
		$output = str_replace(
				array('"user_login"', '"user_email"'),
				array('"user_login_'.$field.'"', '"user_email_'.$field.'"'),
				$output );
		echo $output;
	}
}