Fraud

New Ways to Captcha Bots


It’s not your vision going bad: Those blurry words that some websites force you to retype when you log in are getting blurrier. They’re known as captchas, and they’re designed to stop malicious software from accessing a site and, say, using speedy algorithms to snatch up all the tickets to a concert in seconds. Computers have a hard time deciphering the wavy characters, but they are getting better, says Luis von Ahn, the Carnegie Mellon computer science professor who invented captchas in 2000. ReCaptcha, the company he founded and sold to Google (GOOG) in 2009, still provides more than half of the 280 million captchas solved each day and has had to steadily ratchet up the difficulty, von Ahn says. “It’s tiny, tiny tweaks, making them harder over time.”

The collateral damage, however, is a legion of ever-more-frustrated computer users who resent the average of 14 seconds that they spend deciphering each captcha. “People have really seen the step-up in difficulty,” says Tyler Paxton, a University of Michigan business school graduate and part of a recent wave of entrepreneurs who think they have a better alternative. He says that if the system doesn’t advance, we’ll reach a threshold. “It’s not really, ‘When are computers going to break it?’ but, ‘When is it going to get so difficult for people that they won’t deal with it?’ ”

The solution dreamt up by Paxton and his business school friends Reid Tatoris and Benjamin Blackmer: Mini-games. Their startup, aptly named Are You a Human, has created 10 simple games that, they say, are easy for humans to solve but almost impossible for computers. In one, users see a box with half a dozen or so colored shapes bouncing inside and are asked to drag two red balls into a bin. That sort of spatial-reasoning task is still very hard, if not impossible, for computers to solve, Paxton says.

Paxton first got the idea for the company in 2007 after a friend—he swears it wasn’t him—failed to score Hannah Montana tickets because scalpers’ software programs were able to sneak past the ticketing site’s captcha system and buy up many of the seats. He and his partners founded Are You a Human while at school in 2009 and in October moved into Quicken Loans founder Dan Gilbert’s Detroit business incubator. The nine-person company has raised more than $750,000, and its 10 games, which have thousands of variations, have started running on 38 websites in the last few weeks. The company allows website owners to determine the difficulty level of the games so that a ticketing site subject to lots of scalpers’ attacks could display harder games than a blog.

Are You a Human plans to make money by charging advertisers or websites to design games that integrate their brands, starting at about $25 per 1,000 games played. The company is running tests with a handful of advertisers, including Fathead, a maker of sports-themed decals. The game Are You a Human designed for Fathead required users to drag football helmets into a box.

Solve Media, launched in 2009, doesn’t rely on distorted, hard-to-read words for its captcha alternative. Instead, the New York startup presents users with a list of advertising slogans, and asks them to retype one. The 30-person company charges advertisers, which include 90 major brands such as Toyota Motor (TM) and Symantec (SYMC), about 30¢ per “type in,” and says its captcha-like advertisements are better at building brand awareness than banner ads. Solve is still a distant No. 2 after von Ahn’s reCaptcha, says Chief Executive Officer Ari Jacoby, but its type-ins take half as long to fill. Captchas are “like barbed wire, causing a lot of friction,” Jacoby says.

Jacoby estimates there are 1,200 different approaches to creating captchas, from the default distorted letters to puzzles to matching pictures. Spammers tend to find ways around even the most ingenious defenses, however. Some have even built so-called captcha farms and pay workers about $1 for every 1,000 captchas they solve, according to Paxton.

Von Ahn says captcha farms don’t have enough capacity to pose a real problem to his 12-year-old robot-catching technology, and he’s not particularly worried about any of the new competition. He says he already tried and dismissed games such as Paxton’s because he believes computers can easily be trained to outsmart them. “People don’t like captchas, but they really do stop bots,” he says.

The bottom line: Captchas now take an average of 14 seconds to solve. Startups say their alternatives are easier and may bring in advertising dollars.

Green is Detroit bureau chief for Bloomberg News.

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