A User-friendly CAPTCHA Scheme Based on Usability Features

CAPTCHA is stand for completely automated public turing test to tell computers and humans apart which is the test generated and graded by computers in order to check the users’ humanity. CAPTCHA has benefit to protect online and free services from bots. Bots is defined as software that can access heavily to services without permission. Currently, several different types of CAPTCHA have been proposed in which the main problem is not security that is usability. The way of choosing features of a CAPTCHA that previous researchers have used was not based on the fact of human and computer interaction rules which is to value human part rather than resources. This research studies usability issues of the existing CAPTCHA schemes and proposes a sort of usability features based on what users choose in a user affinity of choice survey. Finally, a sort of usability features is presented and transferred to a user-friendly CAPTCHA scheme as a result of this study. The most important contribution of this study is consideration of people in various ranges of age and people in different languages to be able to solve CAPTCHA. So, it is claimed that the proposed CAPTCHA scheme is a language-independent scheme and also a usable scheme for all ranges of age.