Human-Cognition-Based CAPTCHAs

CAPTCHAs play a significant role in differentiating humans and machines in any Web-based authentication process. With technological advances in text recognition and image extraction, it´s now possible to extract the characters shown in a CAPTCHA with satisfactory accuracy. CAPTCHAs were introduced to cope with the immense threat to online authentication systems, but interpreting them becomes harder for regular Internet users every day. The authors´ alternative CAPTCHA provides a variety of mathematical, logical, and inference problems that only humans can understand and answer correctly. The proposed framework supports question diversity and a user-friendly interface. The authors´ informal user study evaluates the developed system´s performance with different backgrounds. The study shows the efficacy of the implemented system with a good level of user satisfaction.