A User-friendly Image-Text Fusion CAPTCHA for Secure Web Services

Although image-based CAPTCHAs have been introduced to overcome the security level limitation of the previous text-based CAPTCHAs, image-based CAPTCHAs still have problems such as user-unfriendliness in answer inference and wasted transmission cost. To cope with these issues, we propose a novel image-text fusion CAPTCHA model which uses a single image augmented with text hints that helps the users to guess the answers of the CAPTCHA problems more conveniently. According to the experiment results, the proposed CAPTCHA scheme has a higher correct answer rate than that of the previous scheme since the proposed scheme is able to help the users to infer the correct answer of the given CAPTCHA image more easily using the available text hints.