ECC+ - EasyCalcCheck Plus
Protects Joomla! core forms and 3rd party extensions through the integration of anti-spam services and adds an arithmetic problem, a question, a hidden field and a time lock.
With the powerful custom call feature every form can be protected in Joomla! with a special syntax.
Integrated external antispam services: Google ReCaptcha, Akismet, Honeypot Project, StopForumSpam, Mollom, Bot-Trap, Botscout
Protects the backend via a token. Only with the right token, the administrator login site can be opened!
Also included: SQL Injection and Local file Inclusion protection.
Have fun and NO spam! :-)
Joomla! 3 - https://joomla-extensions.kubik-rubik.de/downloads/ecc-easycalccheck-plus/joomla-3
The extension is completely free, but you need a subscription for support: