General intro to reCaptcha

Ever heard of reCaptcha? So what is it?
reCaptcha, a service of Google is a free CAPTCHA tool to protect from spams. CAPTCHA means Completely Automated Public Turing test to tell Computers and Humans Apart. So you can protect your stuffs from the internet bots while allowing human to access the resources. While a bot accesses your resource, it will be rapidly fast and is obvious of being misused.

reCAPTCHA: The FREE anti-bot service that helps digitize books. – As they say.

Then why Google? Why not the other companies with the same service.

reCaptcha from Google is actually the snippets from the old physical books. They scan the book and digitalize the book. The other technology behind is OCR(Optical Character Recognition). In OCR the digitalized image is tried to read using lots of advanced algorithm via computer programs. And the old books ever fails to be read properly.

OCR misinterprets the digital image

reCaptcha makes the user to solve the captcha that machine cannot. And that’s the answer to why Google. Google experiments with lots of Latin books. Google has scanned the physical texts appearing here around (Sometimes the board hanging out on the road comes to your screen, and you’ve to solve). Plus there is an audio CAPTCHA coming along everytime. You don’t need any extra plugins as everything is directly loaded form their server. A line of javascript will do. And they have verify with their own server. So pretty cool.
If you’ve got an WordPress, Joomla, Drupal or Mediawiki, then there’s a plugin to easily embed reCaptcha on your website. They have apis to download and easily communicate with their server for variety of programming platforms.

reCaptcha – default theme

You can learn more here: Learn More

For embedding the reCaptcha in your website, there are few easy steps.
1. First you need to sign up for their API keys, which is absolutely free. Sign Up here.
They will provide you with a Public Key and a Private Key. Public Key, you’ll use this in your javascript and is a public identity for saying reCaptcha server that its you.
And private key is to be kept private. It is used to communicate between your server and reCaptcha server for validation purpose.

Signing up for reCaptcha

2. Now setup your website to work with reCaptcha. Refer to the instruction here.
Here’s a bit of snippet for directly using if you don’t want to look at in-depth of reCaptcha rendering.

<!-- reCaptcha Preferences -->
<script type="text/javascript">
         var RecaptchaOptions = {
            theme : 'red',
            custom_theme_widget: null
         };
</script>

<!-- Load reCaptcha -->
<script type="text/javascript"
    src="http://www.google.com/recaptcha/api/challenge?k=YOUR_PUBLIC_KEY">
 </script>

<!-- If javascript is disabled, then load via iframe -->
 <noscript>
   <iframe src="http://www.google.com/recaptcha/api/noscript?k=YOUR_PUBLIC_KEY"
        height="300" width="500" frameborder="0"></iframe><br>
   <textarea name="recaptcha_challenge_field" rows="3" cols="40">
   </textarea>
   <input type="hidden" name="recaptcha_response_field"
        value="manual_challenge">
 </noscript>

If you are coding your website, there’s a platform specific class or library. You’ll be find it easy to workout. For customization, refer to this link.
reCaptcha comes with four built-in look-and-feel that will perfectly match with the skin. Your site will look more catchy than ever.

reCaptcha look-and-feel

How to customize reCaptcha maintaining the look-and-feel of your website? Or Do you want to code each elements of the reCaptcha by yourself.