Exploring the usability of the dice CAPTCHA by advanced statistical analysis

Abstract

This paper introduces a new study of the Dice CAPTCHA usability based on advanced statistical analysis. An experiment is performed on a population of 197 Internet users, characterised by age and Internet experiences, to which the solution to the Dice CAPTCHA is required on a laptop or tablet computer. The response time, which is the solution time to successfully solve the CAPTCHA, together with the number of tries are registered for each user. Then, the collected data are subjected to association rule mining for analysing the dependence of the response time to solve the CAPTCHA in a given number of tries on the co-occurrence of the user’s features. This analysis is very useful to understand the co-occurrence of factors influencing the solution to the CAPTCHA, and accordingly, to realise which CAPTCHA is closer to the “ideal” CAPTCHA.