Now, software that can crack CAPTCHAs

ImageA
technology startup said that it had come up with software that worksa
human brain in one key way: it can crack CAPTCHAs, the strings of
tilted, squiggly letters that websites employ to make users “prove you
are human,” as Yahoo! and others put it.

San Francisco-based
Vicarious developed the algorithm not for any nefarious purpose and not
even to sell, said co-founder D Scott Phoenix.

Instead, he said
in a phone interview, “We wanted to show we could take the first step
toward a machine that worksa human brain, and that we are the best place
in the world to do artificial intelligence research.”

The
company has not submitted a paper describing its methodology to an
academic journal, which makes it difficult for outside experts to
evaluate the claim. Vicarious offers a demonstration of its technology
at vicarious.com, showing its algorithm breaking CAPTCHAs fromGoogle and
eBay’s PayPal, among others, but at least one expert was not
impressed.

“CAPTCHAs have been around since 2000, and since 2003
there have been stories every six months claiming that computers can
break them,” said computer scientist Luis von Ahn of Carnegie Mellon
University, a co-developer of CAPTCHAs and founder of tech startup
reCAPTCHA, which he sold to Google in 2009. “Even if it happens with
letters, CAPTCHAs will use something else,pictures” that only humans can
identify against a distorting background.

CAPTCHA stands for
Completely Automated Public Turing test to tell Computers and Humans
Apart. They are based on the standard set in 1950 by British
mathematician Alan Turing in 1950: a machine can be deemed intelligent
only if its performance is indistinguishablea person’s.

CAPTCHAs
serve that function: in order to sign up for free email, post comments,
buy tickets or other online activities, more than 100,000 websites
require users to prove they are human by deciphering the squiggly
letters, which are often blurred, smeared and cluttered with dots and
lines.

In practice, someone trying to break CAPTCHAs in order to
do what a site is trying to deter – sign up for umpteen email accounts,
for instance – can easily hire someone to accomplish that. “Most
CAPTCHAs now are broken by paying people in Bangladesh to do it
manually,” said computer scientist Greg Mori of Simon Fraser University
in British Columbia, an expert on machine learning and computer vision.
“For 50 cents an hour, you can get someone to break seven per minute.”

Digitizing books?
Developing
software to break CAPTCHAs would in theory speed that up exponentially.
Vicarious said its algorithm achieves success rates of 90 to 97
percent, depending on the difficulty of the CAPTCHA; a CAPTCHA scheme is
considered broken if a machine can break just 1 percent of the ones it
generates.

That makes “text-based CAPTCHAs no longer effective
as a Turing test,” the company said in a statement, meaning that
CAPTCHAs can no longer be used to tell humanmachine.

That might
be beneficial, experts said. Google’s reCAPTCHA uses wordsold books and
other publications that have been optically scanned but are difficult to
digitize because they are so degraded. “If you can actually solve
reCAPTCHAs, you can digitize old books more easily,” said Mori.

In addition, the algorithm Vicarious uses to break CAPTCHAs might be deployed more widely.

“If
they’ve done it, it could improve the reliability of opticalacter
recognitionthat used in banks to scan checks and by the IRS (Internal
Revenue Agency) to read scanned documents,” said Karl Groves, an
independent website developer who for years has tracked claims about
breaking CAPTCHAs.

The feat required relatively tiny amounts of
data and computing power, Vicarious said, instead using algorithms that
mimic the perceptual and cognitive abilities of the human brain.

The
company has described only in general terms what it hopes to use
artificial intelligence for, describing its goals as building a vision
system modeled on the human brain and developing human-level artificial
intelligence based on what it calls a “recursive cortical network,” for
applications in robotics, medical image analysis, image and video
search, and other fields.

That has been sufficient to attract
more than $15 million in fundinginvestors including Facebook co-founder
and Vicarious board member Dustin Moskovitz. In a statement, he said,
“We should be careful not to underestimate the significance of Vicarious
crossing this milestone,” adding that the company is “at the forefront
of building the first truly intelligent machines.”