WordPress.org

Author: Fili Wiese

Anti-Captcha is a transparent captcha solution which does not require any end-user interaction. It is based on a nonce key, which is dynamically inserted using randomly generated (and obfuscated) javascript.

The aim of this plugin is to prevent automated attacks (by bots) on the following WordPress actions:

• Posting comments
• Logging in
• Registering for a new account
• Requesting a lost password

When a comment is posted without a valid Anti-Captcha token, it shall be instantly marked as spam. This way, you can always manually approve this comment in hindsight if it appeared to be sincere.

For more indepth information about the concept and technique see: The Anti-Captcha Challenge