zxCAPTCHA: New Security-Enhanced CAPTCHA

Abstract

Automated attacks using CNN (Convolutional Neural Network), ML (Machine Learning), and DNN (Deep Neural Network have been successful in bypassing traditional CAPTCHAs. However, Deep Learning techniques, adversarial examples and style neural transfer, have been shown to be particularly effective in protecting CAPTCHAs. In this study, the authors proposed zxCAPTCHA, a new CAPTCHA that combines cognitive-based, image-based, and text-based CAPTCHA characteristics with Deep Learning techniques to improve security. Extensive evaluations were conducted to assess the improvement of the CAPTCHA security. The experiment shows that zxCAPTCHA considerably enhances the security while maintaining comparable usability. We also demonstrate the effectiveness of combining cognitive techniques and Deep Learning to improve CAPTCHA security.