2D captchas from 3D models

Abstract

Existing image-based Captchas (Completely Automated Public Tests to Tell Computers and Humans Apart) utilize huge, public image databases to limit access to websites via image matching attacks. In this paper, a different image based Captcha was developed and prototyped to address the mislabeling and other shortcomings of traditional schemes, which utilize huge public image databases. A database was populated with n 3D models. Then, random rotations, distortions, translations, lighting effects and warping were applied resulting in 2D images. Those 2D images were presented to users for identification to gain access to a website. Users are prompted to identify the object with the label provided through a menu bar. This approach creates an infinite number of 2D images from a 3D model. Therefore, it appears to be impractical for an intruder to algorithmically identify the resulting 2D image without resorting to random guesses. © 2006 IEEE.