Yandex Captcha – this plugin uses the protection from bots and unwanted queries during registration and is also supported by Joomla and is integrated in the CMS. You can configure complexity of the characters from English to Russian – all you need is to get a free API key.
The plugin fully supports the Joomla CMS and its extensions, and can also be used during registration. In the extension are configured: key, type captcha and other data.
It looks like the standard Joomla registration when the plug-in.
Yandex captcha for Joomla.
Support of Joomla extensions.
Simple integration into the available settings and parameters.