Pedometric CAPTCHA for Mobile Internet Users

CAPTCHA requires proof of humanness, thus every CAPTCHA design strives to trace human skills in its user. Many human skills have been explored for designing robust CAPTCHA. In this paper we propose a novel CAPTCHA design for mobile devices. Proposed Pedometric CAPTCHA uses human capability of walking. This paper aims to provide algorithm for implementing Pedometric CAPTCHA, analyze its' usability for persons with various disabilities, perform security analysis and study of user experience. As attacks on CAPTCHA are performed by software bots, human capability of walking or creating acceleration in a mobile device can be effectively used to thwart bots. Usability analysis shows that Pedometric CAPTCHA is accessible for almost all types of disabilities except for the complete motor disability. Study of user experience depicts that 92.2% of the 64 volunteers found the Pedometric CAPTCHA interface to be easy to navigate.