CAPTCHA INTERFACE FEATURE

SECURITY AND USABILITY IN THE DISTINCTION BETWEEN MAN AND MACHINE

Abstract

In order to prevent computers sending automated messages posing as real users, developers have used the interface CAPTCHA feature to distinguish the data population and submissions made by humans and machines. This paper presents the main types of CAPTCHAs, and discusses the implications for usability. To this end, questionnaires were administered and conducted usability tests on three types of CAPTCHA. It was found that, although users are aware of the importance of using the CAPTCHA as a security tool, it was realized that such action undermines the usability, causing dissatisfaction and in some cases, the withdrawal of the task.