Evaluating the Usability of Optimizing Text-based CAPTCHA Generation

Abstract

See, stats, and : https : / / www. researchgate. net / publication / 307547347 Evaluating -based Article DOI : 10 . 14569 / IJACSA . 2016 . 070823 CITATIONS 0 READS 53 1 : Some : Arabic Adaptive View Suliman Qassim 8 SEE All - text , letting . Available : Suliman Retrieved : 16 Abstract—A CAPTCHA is a test that can , automatically , tell human and computer programs apart . It is a mechanism widely used nowadays for protecting web applications , interfaces , and services from malicious users and automated spammers . Usability and robustness are two fundamental aspects with CAPTCHA , where the usability aspect is the ease with which humans pass its challenges , while the robustness is the strength of its segmentation - resistance mechanism . The collapsing mechanism , which is removing the space between characters to prevent segmentation , has been shown to be reasonably resistant to known attacks . On the other hand , this mechanism drops considerably the human - solvability of text - based CAPTCHAs . Accordingly , an optimizer has previously been proposed that automatically enhances the usability of a CAPTCHA generation without sacrificing its robustness level . However , this optimizer has not yet been evaluated in terms of improving the usability . This paper , therefore , evaluates the usability of this optimizer by conducting an experimental study . The results of this evaluation showed that a statistically significant enhancement is found in the usability of text - based CAPTCHA generation .