2009-04-21

What’s Up -- A CAPTCHA Based On Image Orientation

Clipped from: Google Research testing image CAPTCHA's | Googling Google | ZDNet.com

Preventing bots from filling out forms automatically is a hard task. Researchers at Google have been thinking about more effective ways of achieving this goal. You have no doubt seen those jumbled up words that you have to decipher before you can submit a form — well, that’s still to easy for bots to figure out.

Clipped from: CAPTCHA - Wikipedia, the free encyclopedia

CAPTCHA

A CAPTCHA or Captcha (IPA: /ˈkæptʃə/) is a type of challenge-response test used in computing to ensure that the response is not generated by a computer.

Early CAPTCHAs such as these, generated by the EZ-Gimpy program, were used on Yahoo!. However, technology was developed to read this type of CAPTCHA^[1]

A modern CAPTCHA, rather than attempting to create a distorted background and high levels of warping on the text, might focus on making segmentation difficult by adding an angled line

Another way to make segmentation difficult is to crowd symbols together. However, this might be difficult for some people to read

Clipped from: Top 10 Worst Captchas | IT Management and Cloud Blog

Clipped from: Google Research testing image CAPTCHA's | Googling Google | ZDNet.com

Google Research testing image CAPTCHA's

Google Research is experimenting with socially adjusted CAPTCHA’s which require users to orient pictures vertically.

Clipped from: Google Researchers Experimenting Witn New Image “CAPTCHA” Method

The researchers from Google explained that they performed extensive experiments to measure the viability of this technique... Our Captcha technique has achieved high success rates for humans and low success rates for bots, does not require text entry, and is more enjoyable for the user than text-based Captcha.

Below is an example interface, where one needs to slide 3 images into their “natural, upright positions”:

Clipped from: Google tries to beat CAPTCHA crackers with rotated images - Ars Technica

The authors note that the approach leaves plenty of room for further improvement, as the images could be obtained specifically from sources that computers are known to handle poorly, like cartoon content. They also suggest that, should computerized cracking programs ever catch up here, it should be possible to extend the technique into the third dimension using 3D models.

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2008-02-01

CAPTCHA Security Broken

According to a blog post by a Russian security researcher the CAPTCHA system used by Yahoo! may have been compromised.

clipped from www.techlivez.com

CAPTCHA Security Broken - Delight For Spammers

clipped from en.wikipedia.org

Early CAPTCHAs such as these, generated by the EZ-Gimpy program, were used on Yahoo. However, technology was developed to read this type of CAPTCHA^[1].

A modern CAPTCHA. Rather than attempting to create a distorted background and high levels of warping on the text, this CAPTCHA focuses on making segmentation difficult by adding an angled line.

Another way to make segmentation difficult. Crowded symbols can be read by humans but can't be segmented by bots

clipped from network-security-research.blogspot.com

Network Security Research and AI

Yahoo! CAPTCHA is broken

Few months ago we received information that yahoo CAPTCHA recognition system exists in the wild with the recognition rate about 30%. So we decided to conduct few experiments. We explored yahoo CAPTCHA and designed a similar system with even better recognition rate (about 35%). The vendor was notified. The vendor didn't reply. In this article we’ll present you our own research.

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