<p>yaCAPTCHA is a CAPTCHA plugin for WordPress that helps you block comment spam<br />
from automated bots. In order to post comments, users will have to write down<br />
the characters that are part of an image. Since it is relatively hard for<br />
automated programs to figure out those characters, this will help prevent<br />
comment spam from those programs.</p>
<h4>Requirements</h4>
<ul>
<li>WordPress 1.5 or higher.</li>
<li>PHP 4.1.0 or higher with GD2 library support.</li>
<li>Theme must support the ‘comment_form’ action.</li>
<li>PHP sessions enabled and properly configured.</li>
</ul>
<p>In case you are wondering, most hosting providers should have those basic<br />
requirements in place.</p>
<h4>Strengths vs other solutions</h4>
<ul>
<li>Easy to install</li>
<li>Does not require Javascript to work</li>
<li>Broad WordPress version support</li>
</ul>
<h3>Thanks</h3>
<p>Thanks to Kruglov Sergei for creating KCAPTCHA, his pretty good CAPTCHA. You<br />
can visit KCAPTCHA website <a href="http://www.captcha.ru/en/kcaptcha/" title="KCAPTCHA
website">here</a>.</p>


yaCAPTCHA

yaCAPTCHA is a CAPTCHA plugin for WordPress that helps you block comment spam from automated bots.

algorhythm

<p>This Plugin integrates the Google reCAPTCHA Service Modul in the BuddyPress Template Page ‘register.php’. The file is located in ‘/wp-content/themes/{name}/registration/register.php’. The plugin adds the new feature by adding an action on ‘bp_before_registration_submit_buttons’. Therefore the ‘register.php’ must contain the line ‘do_action( ‘bp_before_registration_submit_buttons’ )’. My one was generated with the famous plugin <a href="https://wordpress.org/extend/plugins/bp-template-pack/" rel="ugc">BuddyPress Template Pack</a>. It makes a normal WordPress-Template ready for use with <a href="https://wordpress.org/extend/plugins/buddypress/" rel="ugc">BuddyPress</a>. The missing files in the template will be added.</p>
<h4>Some Features</h4>
<ul>
<li>not yet, the plugin has no admin-page, but it will follow</li>
<li>at the beginning of the ‘bp-recaptcha.php’ are some variables to add/change the <a href="https://www.google.com/recaptcha/admin/create" rel="nofollow ugc">reCAPTCHA Api keys</a>, style of reCAPTCHA, language and texts</li>
</ul>
<h4>Languages</h4>
<ul>
<li>English, but can be switched very simple</li>
</ul>
<p>Notice: The installation of this plugin will require additional work. Edit the ‘bp-recaptcha.php’ file to make your settings.</p>


BuddyPress reCAPTCHA

I found this plugin amazing so I forked it to create an easy to use admin panel: https://wordpress.org/plugins/buddypress-captcha/
Thanks!



AMAZING!! I forked it

This plugin utilizes reCAPTCHA to help your blog stay clear of spam-registrations.

yaCAPTCHA vs BuddyPress reCAPTCHA