Have you noticed those squiggly styled words while registering at a website? Well that is Captcha technology. Its a contrived acronym and stands for Completely Automated Public Turing test to tell Computers and Humans Apart. All the bold words coming together form CAPTCHA.

Most Email sites use this technology. Gmail, Hotmail and Yahoo use it! CAPTCHA technology was evolved first because of the many bots that were created on the web to spam internet sites of various content and email providers. Automated sign in created new users suddenly and could overload the servers.

What does CAPTCHA do ?

It makes those words squiggly which have to be entered for registering.

• Current Software are unable to solve it accurately.
• Most humans can solve it accurately.
• Does not rely on being new to the attacker which means constant upgrades are not necessary.

Most Captcha developers recommend the use of reCaptcha a service which uses Captcha and then carries out digitization of the content. reCaptcha is currently working on converting all published work of The New York Times over the past 130 years into digital format.

Google was reportedly working on a Captcha like technology until May 2009. Well instead of reinventing the wheel they decided to go buy the wheel itself and Google announced through its blog and on twitter that they have acquired reCaptcha.

reCaptcha has this unique technology which captures a image and scans it and then converts it into text. Ideal for Google Books and Google News

Links: Captcha | reCaptcha | Google Blog