Gestalt geometric CAPTCHA

This research investigated a new Image-Based CAPTCHA called Gestalt Geometric CAPTCHA, which does not require the use of a database of images, and is based on the Gestalt Theory of human recognition. The aim was to develop a type of CAPTCHA that is easier for human users and harder for bots. We experimentally tested the use and effectiveness of Gestalt Geometric CAPTCHA in terms of time for completion, authentication pass rate, and user satisfaction, in comparison with reCAPTCHA, Ironclad CAPTCHA, and ShapeCAPTCHA. We also tested our novel CAPTCHA for robustness against two shape detection and classification programs, ShapeChecker and Shape-detect. The results were promising, but some issues remain for future improvement.