I use the "Did You Pass Math" plugin for WordPress, which asks a simple math
problem in text ("What is the sum of four and three?").  I've had no
complaints from users, and no spam.

***********
Jim Tobias
Inclusive Technologies
[log in to unmask]
+732.441.0831 v/tty
www.inclusive.com
 

> -----Original Message-----
> From: John Nissen [mailto:[log in to unmask]] 
> Sent: Saturday, August 05, 2006 3:00 PM
> To: [log in to unmask]
> Subject: New "Captcha" to replace "distorted letter" tests, 
> protecting sites.
> 
> Hi all,
> 
> Up till now, some sites have protected themselves using a 
> "captcha" test that involves the user recognising some 
> squiggly letters, which cannot be done automatically by 
> software, until now.
> Perhaps a new test approach should be developed, which does 
> not exclude vision impaired people.
> 
> Cheers,
> 
> John
> 
> John Nissen
> Cloudworld Ltd - http://www.cloudworld.co.uk maker of the 
> assistive reader, WordAloud.
> Tel: +44 208 742 3170  Fax: +44 208 742 0202
> Email: [log in to unmask]
> 
> 
> 
> ----- Original Message -----
> From: <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Monday, July 24, 2006 1:00 PM
> Subject: [Webwatch] seattletimes.com: Researchers try to 
> create newdistorted-letter test
> 
> 
> > This message was sent to you by [log in to unmask], as a service of 
> > The Seattle Times (http://www.seattletimes.com).
> >
> > 
> ----------------------------------------------------------------------
> >
> > Researchers try to create new distorted-letter test Full story:
> > 
> http://seattletimes.nwsource.com/html/businesstechnology/2003147633_bt
> > captchas24.html
> >
> > By Crayton Harrison
> > The Dallas Morning News
> >
> >
> >
> > DALLAS -- Computers are better than humans at a lot of complex 
> > calculations, but we still have them beat on some small problems.
> >
> > That's why a very simple test has protected some of the world's 
> > biggest Web sites for so long. Go online to perform a 
> routine task -- 
> > buying sports tickets, say, or sending an e-mail or commenting on a 
> > blog -- and you'll see a picture of random squiggly letters.
> >
> > The Web site asks you to type the letters you see, something a 
> > computer can't do without sophisticated programming. That keeps 
> > hackers from using software to repeatedly enter information on the 
> > sites, sending spam through online e-mail services or blogs.
> >
> > But the defenses are crumbling. Computer scientists are working on 
> > replacements for the test, knowing that computers are 
> learning to read 
> > even the messiest scribbles.
> >
> > Lost ground
> >
> > The distorted-letter test "is getting to the point where 
> it's almost 
> > defeated" by computer scientists in the laboratory, said 
> Luis von Ahn, 
> > a postdoctoral fellow at Carnegie Mellon University's 
> computer-science 
> > department. "The ones not yet defeated by computers are 
> really hard to 
> > read for humans. But they'll be defeated pretty soon."
> >
> > Researchers aren't trying to beat the distorted-letter 
> tests to ambush 
> > Web sites, of course. They use it to make computers better at 
> > recognizing text.
> >
> > But if computer scientists can figure out how to beat the tests, 
> > hackers won't be far behind. The next wave of tests will have to 
> > present problems that computer researchers and cybercriminals have 
> > barely begun to tackle with artificial intelligence.
> >
> > Carnegie Mellon's research team trademarked a name for these 
> > computer-or-human tests: captcha. It's an acronym that stands for 
> > "Completely Automated Public Turing test to tell Computers 
> and Humans 
> > Apart." Turing refers to Alan Turing, a British logician 
> who proposed 
> > a theoretical test to judge whether computers were good at 
> imitating humans.
> >
> > The current captchas have protected Web sites for a remarkably long 
> > time in the ever-changing Internet world. Researchers at the 
> > pioneering search engine site AltaVista created one of the first 
> > squiggly-letter tests in the late '90s.
> >
> > "Humans are much better at recognizing patterns than 
> computers are. A 
> > 3-year-old can tell apart a man from a woman. Computers 
> cannot do that,"
> > said Andrei Broder, who was AltaVista's chief scientist at the time.
> >
> > Other researchers and companies began developing their own 
> versions of 
> > the test. Ticketmaster added one in 2002, and it's become 
> an important 
> > part of the company's defense against scalpers.
> >
> > "There are not a lot of ways, at the end of the day when a 
> transaction 
> > is being made, to tell if someone is an automated bot or a 
> human, and 
> > this helps us to identify that," said Bonnie Poindexter, a 
> spokeswoman 
> > for the ticketing agency owned by IAC/InterActiveCorp.
> >
> > Several varieties
> >
> > The character-recognition tests come in several varieties. 
> > Ticketmaster uses a string of letters that don't appear to 
> be warped 
> > much. But diagonal lines crisscross around them, and the 
> background is sometimes grainy.
> >
> > Google's Blogger service, on the other hand, uses no 
> background. But 
> > the letters roll and swirl as if they have been caught in a wave.
> >
> > There are ways to beat the text-based captchas, and not all of them 
> > are high-tech. Some computer experts have done it simply by looking 
> > for patterns in the random characters or the computer 
> language used to 
> > generate them. Some hackers have been rumored to pay people 
> to enter 
> > the correct information or entice them to do it by offering 
> free pornography.
> >
> > But computer researchers are also beating text captchas simply by 
> > developing computers that are sophisticated enough to read them. In 
> > the same way that supercomputers have been developed to beat chess 
> > masters by making millions of decisions in an instant, 
> computers also 
> > can learn to "read" and detect patterns by making a series 
> of complex calculations.
> >
> > Fortunately, people can still find patterns in other ways 
> that stymie 
> > computers. Carnegie Mellon's Pix program, for instance, shows four 
> > pictures that have relatively little to do with each other 
> except for 
> > one common element -- a cow, or a cup. Other researchers are also 
> > experimenting with image-based captchas.
> >
> > And some sites, including the Blogger service, offer an audio 
> > alternative for people with visual impairments. In the 
> audio test, a 
> > voice speaks a series of numbers over a staticky 
> background, and the 
> > user must type the correct sequence to access the site.
> >
> > Researchers continue to tweak the text-based captchas, too, using 
> > colorful backgrounds or breaking the letters apart to fool 
> the bots. 
> > But with every change, they face the danger of making the 
> captcha too 
> > difficult for people to read.
> >
> > Other concerns
> >
> > Advocates for Web users with disabilities already are 
> concerned that 
> > captchas keep the visually impaired from accessing the 
> sites they need.
> >
> > Text-based captchas have another problem. It's unclear who owns the 
> > rights to the technology.
> >
> > When AltaVista developed its test, Broder and his team 
> patented the idea. 
> > Through several mergers and acquisitions, the patent fell into the 
> > hands of Hewlett-Packard.
> >
> > HP no longer owns the patent, said Brigida Bergkamp, a 
> spokeswoman for 
> > the technology giant. She declined to disclose what had happened to 
> > the patent.
> >
> > Carnegie Mellon researchers must decline requests for software code 
> > for text captchas because the patent rights are unclear, 
> von Ahn said. 
> > "We're a little upset about that," he said.
> >
> > But it may not matter, since text captchas are becoming 
> more and more 
> > vulnerable.
> >
> > "We knew this was going to happen. It was just a matter of 
> time," von 
> > Ahn said.
> >
> > 
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