An evaluation of the interactive video CAPTCHA method against automated attack

Abstract

CAPTCHA is designed to detect automated programs (called bots) by requiring them to perform tasks that are easy for humans but difficult for automations. CAPTCHAs are vulnerable to relay attacks in which the challenges are relayed to remote human-solvers. In our previous paper, we proposed an interactive video type CAPTCHA that is strongly resistant to relay attacks. However, a quantitative evaluation of resistance to automated attacks still has not been carried out. Herein, we implement an automated attack for applying to our CAPTCHA and evaluate its resistance to automated attacks. Our results show the robustness of our proposed method against mean shift algorithm.