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. 


Sources:

  1. Google Research testing image CAPTCHA's | Googling Google | ZDNet.com
  2. CAPTCHA - Wikipedia, the free encyclopedia
  3. Top 10 Worst Captchas | IT Management and Cloud Blog
  4. Google Researches New Captcha Approach In Which Users Rotate Images Upward
  5. Google Researchers Experimenting Witn New Image “CAPTCHA” Method
  6. Google tries to beat CAPTCHA crackers with rotated images - Ars Technica
Related:
  1. Official Google Research Blog: Socially Adjusted CAPTCHAs
  2. rotcaptcha.pdf (application/pdf Object)
  3. Google boffins unveil 'What's Up?' CAPTCHA • The Register
  4. iTWire - Which way up is Google?