Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers crack security system designed to block Internet robots

11.12.2002


For every warm-blooded human who has ever taken an online poll or signed up for free web-based email, there are legions of computer-automated Internet robots, or "bots," trying to do the same thing.



A clever security system designed to stop these bot programs - which contribute to the Internet equivalent of computer-generated telemarketing calls - has now been cracked by a pair of computer scientists from the University of California, Berkeley.

Researchers at Carnegie Mellon University in Pittsburgh created the security system, known as Gimpy, to thwart the bot programs that relentlessly scour cyberspace for opportunities to register new email addresses, stuff ballots for online polls and direct unwitting participants in Internet chat rooms to advertisements. Bot-produced email accounts are hard to block or trace, making them ideal vehicles for sending spam to legitimate email users.


The UC Berkeley effort was a response to an open challenge by the research team at Carnegie Mellon to the computer science community to write a program capable of reading the Gimpy-distorted text.

Gimpy takes advantage of the fact that most people can easily recognize words with letters that are squiggly, fuzzy or otherwise distorted. In contrast, computer programs, such as those based upon optical character recognition (OCR) technology, are easily flustered if the text is not clear and free of background clutter.

Last year, Yahoo, one of the largest providers of free web-based email, implemented the Gimpy check as part of the new account registration process. People who can pass the test by typing in the correct word shown on the screen can go on to get an account. Bots, presumably, are stopped cold.

"We were able to crack Gimpy because of our previous research on a technique called ’shape contexts’ for object recognition," said Jitendra Malik, professor and chair of the Division of Computer Science at UC Berkeley’s College of Engineering. "The basic idea is to match shapes based upon the relative configuration of contours in a way that can tolerate small distortions. We had applied the technique before to handwritten digits and human figures, as well as to three-dimensional objects, so it seemed plausible to try it here."

It took five days for Malik and Greg Mori, computer science doctoral student at UC Berkeley, to create the program, which works by comparing the distorted letters in the given field to the 26 letters of the alphabet. Algorithms then come up with three to five likely candidate letters and group them in pairs that are analyzed to see whether they can be joined to form complete words. The resulting words are then scored based upon how closely the letters matched the image in the field. The word with the best score is then chosen.

Mori compared the process to detecting arms, legs and a head in an image to come up with the conclusion that a human is depicted.

In a trial using 191 images, the process worked 83 percent of the time for the simplest version of Gimpy, known as EZ-Gimpy, which "hides" a single word amid a cluttered background. This is the version used by Yahoo in the email registration process.

In a more difficult version of Gimpy, as many as five pairs of distorted words are presented with the word pairs superimposed upon each other. The user must then ferret out three correct words to pass the test.

"Breaking this harder version of Gimpy is still a work in progress because recognizing letters that are pasted on top of each other is more difficult," said Mori. "At this point, our success rate for the more challenging Gimpy is 30 percent."

Gimpy is one of several different programs in a project called CAPTCHA, which stands for "Completely Automated Public Turing test to Tell Computers and Humans Apart," headed by Manuel Blum, professor of computer science at Carnegie Mellon University, with his graduate student, Luis von Ahn. Before joining Carnegie Mellon, Blum taught computer science at UC Berkeley for 30 years.

Malik said the Gimpy challenge is a great test for the ongoing research in computer object recognition he and others at UC Berkeley are conducting. "We’re looking at the bigger picture, so to speak," he said. "The goal of the computer vision research we are doing is to develop programs that can recognize people, animals and other objects in a picture. It’s a shift from programs that can simply read text to those that can actually see pictures, which is a major step forward in the field of artificial intelligence."

Once Malik and Mori successfully cracked the EZ-Gimpy system, they notified Blum at Carnegie Mellon.

"I was delighted when I heard from them," said Blum. "They were the first ones to successfully take up the challenge."

Blum said that he hopes this research will eventually bring online the wealth of materials in the Library of Congress, which has been a daunting task because of the difficulty current scanning software has in "reading" handwritten or manually typed text.

Blum noted that Carnegie Mellon’s Gimpy would be much more difficult to crack than EZ-Gimpy.

"They’ll keep making it harder, and we’ll keep working to break it," said Malik. "It’s great fun."

Sarah Yang | EurekAlert!
Further information:
http://www.berkeley.edu/news/media/releases/2002/12/10_gimpy.html

More articles from Information Technology:

nachricht Putting food-safety detection in the hands of consumers
15.11.2018 | Massachusetts Institute of Technology

nachricht Next stop Morocco: EU partners test innovative space robotics technologies in the Sahara desert
09.11.2018 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>