SemCAPTCHA—user-friendly alternative for OCR-based CAPTCHA systems

In this paper we present a new CAPTCHA system (Completely Automated Turing Test To Tell Computers and Humans Apart). This proposal, SemCAPTCHA, is motivated by an increasing number of broken OCR-based CAPTCHA systems and it is based not only on text recognition but also on text understanding. We describe SemCAPTCHA from both user’s perspective and system’s perspective and compare it to some currently popular CAPTCHAs. We also briefly describe an experiment carried out to test our CAPTCHA on human users.