aomm

火柴手写码，是将海量手写图片资源进行碎片化处理，随机组合、加密而成；由于源数据重复概率低、手写文字差异大（即使同一个人多次书写同一数字，? ?结果也不尽相同）、手写字符书写不规则等特点，使得现有OCR技术很难识别；同时我们结合大数据处理和云计算技术，为开发? 提供? 晰、安? ?、方便的云验证码服务。

火柴手写码

火柴手写码，是基于海量手写字符、复杂安全技术而生成的图片验证码，提高了破解难度。火柴手写码，由火柴棍工作室研发，其开放平台已为开发者提供清晰、安全、方便的云验证码服务。

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.

火柴手写码 vs Cookies for Comments