By Carrie Wells, The Baltimore Sun
April 27, 2014
While blind people can browse the Internet through a variety of means, there is often one thing that stops them cold — a security feature known as a CAPTCHA that's designed to distinguish human users from robots.
CAPTCHAs, in which a user must identify the letters in a distorted image, are commonly used to block automated bots from grabbing up all the tickets for an event, signing up for thousands of email addresses in a short period of time or unfairly swaying the results of an online poll. They have drawn criticism from advocacy organizations for the blind for being too difficult to use, but last month, Towson University secured a U.S. patent for a new kind of CAPTCHA that's intended to be easier for those with limited or no eyesight.
With Towson's SoundsRight CAPTCHA, users listen to a series of 10 random sounds and are asked to press the computer's space bar each time they hear a certain noise — a dog barking, a horse neighing — among the other sounds. The developers say it is superior to Google's current audio alternative CAPTCHA, citing studies showing that version's failure rate of 50 percent for blind users.
"Blind people are capable of doing everything that a visual person can on the Internet," said Jonathan Lazar, a Towson professor who has led a group of graduate and outside researchers on the project. "We just try to come up with some equivalent features that make it easier."
"Some people are unaware that blind people can use the Internet," Lazar added.
The SoundsRight CAPTCHA is still in a "beta" version, Lazar said, and the developers are hoping a real-world rollout will help identify any necessary tweaks.
The Towson researchers worked closely on testing with the National Federation of the Blind, which is headquartered in the Riverside neighborhood of Baltimore. Anne Taylor, the federation's director of access technology, said there are several types of software available for blind users to read the text on a Web page aloud. Taylor, who is blind, said not being able to use visual CAPTCHAs could impede a blind person's ability to enjoy the benefits of the Internet and hurt their ability to hold a job.
A sighted person could help a blind user with the visual CAPTCHAs, she said, but the blind want to be independent on the Internet. Further, since many CAPTCHAs are on web pages that ask for personal financial information, she has concerns about privacy.
"The Internet is such an important and integral part of our daily lives now," Taylor said. "Just think of how many hours you spend on the web as a sighted individual. Would you really want to have someone with you all that time?"
CAPTCHA, which stands for Completely Automated Public Turing test to tell Computers and Humans Apart, was introduced as a concept by computer scientist Alan Turing in 1950. The term was coined in 2000 by researchers at Carnegie Mellon University who developed an early Web page test program for Yahoo.
The CAPTCHAs protect from automated hacking programs that can also leave spam comments on blogs, attack protected passwords and send junk email.
Tim Brooks, the chief software developer on the SoundsRight project since 2010, said the audio CAPTCHA can be embedded into any Web page and customized by the webmaster. Brooks said its script could be tweaked to be used in any number of different languages or have users identify any number of sounds. An organization for train enthusiasts, he said, could potentially have users identify the sounds of different types of trains.
The SoundsRight CAPTCHA is just as secure as the traditional visual CAPTCHAs, he said. Sighted users can use the audio CAPTCHA as well, or a Web page could give the option of either a visual CAPTCHA or the SoundsRight CAPTCHA, he said. The only potential downside to the technology is that it takes about 30 to 40 seconds to complete, versus less than 10 seconds for a visual CAPTCHA, Brooks said.
"A lot of people don't have that kind of patience," he said.
The Towson CAPTCHA project was the brainchild of then-undergraduate student Jon Holman in 2007 as a class project, Lazar said. In a 2007 focus group, blind users identified visual CAPTCHAs as the biggest impediment to their using the Internet independently. Several other students, faculty members and outside researchers have assisted in developing the technology since the project began.
"We've always done the evaluation with blind users at every step," Lazar said. "This was research that was done because blind users were telling us this was important."
The project was partially supported with a $50,000 grant from the Maryland Technology Development Corp., Lazar said. The researchers went through several different prototypes, rejecting those that weren't found to be secure enough.
The SoundsRight CAPTCHA is in use on the National Federation of the Blind's website, and the organization is working to encourage various groups and businesses to adopt it.
"We are all one step away from a sudden disability, so why not make the Internet an inclusive place for everybody?" Taylor said.
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