WordPress KV reCaptcha plugin will help you to spam registrations and help you to prevent brute force attack..
If you want to rework with the code, fine take look at here before start usging this code, It will be helpful to work with your own project.
Enable disable options you can extend it to use the recaptcha for comment form and contact form..
Admin Interface. reCaptcha on registration page...
Upload kv recaptcha to the wp-content plugins directory.
Activate the plugin through 'Plugins WordPress...
Activate the plugin through 'Plugins WordPress...
The following people have contributed to this plugin..
Browse the code, check out SVN repository, or subscribe to the development log by RSS...
Read more