dannyx

This is my first WordPress plugin that i made it for personal use and to learn how to build plugins. 
This plugin replaces the submit button on the post comment section with a set of buttons from images. 
A small message provides the user a hint on what button to use to submit the comment. 
Demo: http://www.arcweb.ro/blog/2011/12/21/testing-cutecaptcha-plugin/
Requirements: 
PHP mcrypt should be available on the server, i will add more encryption methods if required. 
Session support is optional, supports caching of post pages without session but with lower security.
Customize: 
All the information and parameters to configure are in cutecaptcha.php 
The images and messages can be customized and should be quite fun to adapt it with the 
subject of each website, especially expecting that anybody that wants to post a comment 
should have a good idea about that subject.
Security: 
The variety in images and messages will make it difficult for automated bots to break it. 
The plugin is intended for a regular blog that will never attract dedicated spamers. 
At this moment the association between messages and photos can be analyzed, but it is possible to add 
another layer of protection if required. I strongly suggest that each site uses personalized images and 
messages related to their content.
TODO: 
Alternative encryption functions for servers without php mcrypt. 
Extra layer of security on images: Raw data inserted in file, modified with 
variable watermarks for each session. 
Display a specific number of buttons from a gallery of buttons. 
IP Block: block ip’s after a number of failed submits for a number of days.

Cute Captcha

Replaces the submit button  with a set of buttons from a set of images. A small message provides the user a hint on what button to use.

Automattic

Donncha O Caoimh (a11n)

This plugin adds a stylesheet or image to your blog’s html source code. When a browser loads that stylesheet or image a cookie is dropped. If that user then leaves a comment the cookie is checked. If it doesn’t exist the comment is marked as spam. 
The plugin can also check how long it took a user to enter a comment. If it’s too fast it’s probably a spam bot. How fast can a legitimate user enter their name, email, web address and enter a well thought out comment?
For the adventurous, add these lines to your .htaccess and it will block spam attempts before they ever get to WordPress. Replace the Xs with the cookie that was set in your browser after viewing your blog. You can also find the cookie value by examining the page source code and looking for “css.php?k=XXXXXXXXXXXXXXXXXXX”. Make sure the lines go above the standard WordPress rules.
<pre><code> RewriteCond %{HTTP_COOKIE} !^.*XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.*$
 RewriteRule ^wp-comments-post.php - [F,L]
</code></pre>
If you use WordPress MU, replace wp-comments-post.php above with wp-signup.php to block spam signups.
<pre><code> RewriteCond %{HTTP_COOKIE} !^.*XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.*$
 RewriteRule ^wp-signup.php - [F,L]
</code></pre>

Cookies for Comments

If you don't use any other spam filter plugins, then you can rely on this to stop spam comments for sure!

Must have, if you don't use any other spam filters!

I'd been getting a dozen spams a day on two of my sites. We installed "Stop Spam Comments" on one and "Cookies for Comments" on the other. Both worked perfectly. No more spam. Thanks!



very easy and no more spam!

Sets a cookie on a random URL that is then checked when a comment is posted. If the cookie is missing the comment is marked as spam.

Cute Captcha vs Cookies for Comments