Integrating Captcha with MediaWiki

With reCAPTCHA you can protect your websites against spam and help the Internet community at the same time. Read on to find out how

Monday, August 04, 2008

Captcha, also known as Completely Automated Public Turing test, is a program used to distinguish between a human and a bot. You might have used Captcha while filling an online form or posting comments on a blog. Just to refresh your memory, these are images containg numbers or words that you are asked to enter in a box. This is to verify that a human is filling the form and not a bot. The captcha images are designed in such a way that it is hard for computer programs to read them. Captchas are used to preventing against bots registering on a website, protecting spam comments in blogs, preventing brute force attacks on a website to bypass authentication, etc. reCAPTCHA is one such captcha provider, which we will talk about in this article.
Humans solve around 60 million CAPTCHAs every day and so reCAPTCHA decided to utilize such efforts to the process of digitizing books. These books are first scanned and photographic images are then changed into text through OCR. Now OCR doesn't read all images, so somebody needs to enter them. reCAPTCHA sends these words as captcha images to users. To ensure proper authentication, correct answers of first word of reCAPTCHA are known, while OCR cannot read correctly the second word.

Using reCAPTCHA with MediaWiki
To get started you need to acquire Public and Private Keys from reCAPTCHA's website. To do this, simply register your domain name on reCAPTCHA's website and it will automatically generate keys for you.

In reCAPTCHA, you are asked to enter two words for authentication unlike other captchas.

Once you have acquired the keys from reCAPTCHA's website, download its Mediawiki extension from http://code.google. com/p/recaptcha /downloads/list?q=MW-Latest. Now simply unzip this file and upload it to extensions directory of Mediawiki.

Now open MediaWiki's LocalSettings.php file and add following lines to it.

require_once("$IP/extensions/recaptcha/ReCaptcha.php" );
$recaptcha_private_key = ' ';
$recaptcha_public_key = ' ';

Here between single codes enter Public and Private Key which you acquired earlier from reCAPTCHA's website. Now open 'Create account page' of MediaWiki. You will see a reCAPTCHA image with the create account form. In case a user cannot see the image, he can click on 'Get an Audio challenge' and it will play an audio file, which will have eight numbers. The users will be asked to enter those numbers. reCAPTCHA also comes with plug-ins for Joomla, phpBB and other applications which can be found on its website.

Page(s)   1