AJIGJAX: A hybrid image based model for Captcha/CaRP

Captcha is a challenge-response test to segregate humans from automated programs like bots. Captcha are available in various forms such as image based, puzzle based, audio based and video based Captcha. Every Captcha is prone to attacks such as robots-in-the-middle attack and humans hired to solve the Captcha. Websites which needs little or no authentication requires less security while other websites which needs user authentication due to confidential information, requires secure access. Depending on the security requirements, different forms of Captcha are required. In this paper, we propose a novel Captcha scheme which addresses the issues faced by existing Captcha schemes. The proposed scheme is like a game so it will be more entertaining for humans to solve. AJigJax Captcha requires no or small database on server. The proposed scheme includes all essential features such as memorability, usability and security against human bombs. The performance analysis of proposed AJigJax Captcha, based on drag and drop functionality, shows that 75% of respondents supported AJigJax Captcha and believes that it must be implemented in real life scenario. 87.5% of respondents prefer using mouse rather than keyboard to solve the Captcha and 92.5% of respondents were successfully able to solve all the rounds of the proposed Captcha scheme.