The Man Who Invented The Captcha

Tue, Jun 4, 2013, by Ruby Hawk

Web Talk

Have you ever wondered who came up with the idea of the CAPTCHA? It was originated to tell automated spammers from real people, and was invented by a young college student who later sold the patent to Google.

In 2000 when email was the big thing, spammers created hundreds of accounts automatically to use on sites selling popular tickets, obtaining the best seats they later sold to the public at higher prices. Websites needed some way to distinguish between real people and automation. That’s when Mr von Ahn, who was attending Carnegie Mellon University in Pittsburgh, and his PhD advisor came up with a solution. It had to be a test that humans could pass, but automation couldn’t.

They first tried an animal on roller skates, or something of the kind. The problem with that idea was that people were not very good at identifying images. Their next try was the scrambled letters we see today and it worked. It’s called the CAPTCHA. We all know it well. In case you want to know what all the letters stand for its, “Completely Automated Public Turing test to tell Computers and Humans Apart” Mr von Ahn went on to get his doctorate, plus a call from Bill Gates with an offer of a job, which he turned down.

Mr von Ahn went on to create esp games with a purpose, where two players in two different locations are shown the same image in their web browsers, and asked to type words describing the image. The round ends when the two players type the same word. The aim is to find the most obvious descriptive words. Google bought the technology in 2005.

By this time the CAPTCHA was being used every day by INTERNET users around the world at about half a million hours daily. It improved the security of the INTERNET, but what a lot of wasted man power. So, Mr von Ahn decided to find a way to cut short those wasted hours. It was a modified CAPTCHA. His idea was, instead of using random letters, why not show words from scans of old newspapers that automated document digitization systems could not understand. They could be shown to people as a modified CAPTCHA test. It’s called the reCAPTCHA. Google also acquired it in 2009.

Mr von Ahn has won many prizes plus a presidential award in science and many patents in his name. He is still in his early thirties and he isn’t about to stop. He has other up and coming projects we will continue to hear about in the future.

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