Computer and Information Technology, International Conference on (2010)
Bradford, West Yorkshire, UK
June 29, 2010 to July 1, 2010
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/CIT.2010.117
An increasing number of public web services have attempted to prevent exploitation by bots and automated scripts, by requiring a user to solve a Turing-test problem, namely a ”Completely Automated Public Turing test to tell Cmputers and Humans Apart (CAPTCHA)”, before they are allowed to use web services. In this paper, we present an effective image-based CAPTCHA based on the orientation of N-gonal cropped sub-images as a solution of CAPTCHAs. Our CAPTCHA is based on the difficulty of detecting the orientation of N-gonal sub-images. In our CAPTCHA, the number of orientations and the crop size are important considerations, since our CAPTCHA requires users to find the orientation of sub-images cropped in the form of a regular polygon. So, we discuss usability of our CAPTCHA and the efficient values of the number of orientations and the crop size through user experiments and SVM-based machine learning tests in this paper.
Image-based CAPTCHA, Usability, Random attack, Machine learning, Perceptual recognition
Woo-Keun Chung, Hwan-Gue Cho, Jong-Woo Kim, Seon-Yeong Kim, "Detecting the Orientation of N-gonal Cropped Sub-images and Its Application", Computer and Information Technology, International Conference on, vol. 00, no. , pp. 552-559, 2010, doi:10.1109/CIT.2010.117