# Topics > Risk of AI > Control of AI and robots >  CAPTCHA and reCAPTCHA

## Airicist

CAPTCHA on Wikipedia




> A CAPTCHA (an acronym for "Completely Automated Public Turing test to tell Computers and Humans Apart") is a type of challenge-response test used in computing to determine whether or not the user is human.

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## Airicist

Using Human Computation and reCAPTCHA to Digitize Old Books, with Luis von Ahn 

Published on Nov 18, 2014




> Back at the beginning of the century, Luis von Ahn helped invent CAPTCHA, the online security device featuring squiggly letters that you have to re-type in order to prove you're human. In 2007, von Ahn invented reCAPTCHA, a new form of CAPTCHA that serves a second purpose: the digitization of old books. In this video clip, von Ahn describes how reCAPTCHA works while discussing the power of human computation, a term he helped coin that describes the harnessing of both human and computer abilities in order to accomplish difficult tasks.
> 
> Read more at BigThink.com: 
> "Why Humans Can Solve Some Problems Better Than Computers, with Luis von Ahn"
> 
> by Big Think Editors
> November 18, 2014
> 
> Transcript: So human computation, the idea, is that there are problems that computers cannot yet solve. It's funny because some of these problems are very simple problems seemingly. For example, a computer cannot tell you what's inside an image. They can tell you somethings but it can't really quite tell you there's a cat next to a dog and they're both running. A computer can't do that. Well humans, we can do it super easily. And there are many things that computers cannot do that humans can. Conversely, there are also things that computers can do that humans can't do. I mean computers can multiply humongous numbers, humans may be able to do it but very slowly and we're error-prone. And so the idea with human computation is to combine both humans and computers together in a very large scale to solve problems that neither can solve alone.
> ...

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## Airicist

Article "Artificial Intelligence Beats CAPTCHA"

by Charles Q. Choi
October 26, 2017

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