IllusionCAPTCHA: A CAPTCHA based on Visual Illusion
Apr 28, 2025·
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1 min read
Ziqi Ding
Gelei Deng
Yi Liu
Junchen Ding
Jieshan Chen
Yulei Sui
Yuekang Li
Abstract
IllusionCAPTCHA uses visual illusions to create CAPTCHA tasks that are intuitive for humans but confusing for multimodal LLMs. The work evaluates LLM CAPTCHA-solving behavior and designs misleading options that steer models toward incorrect answers while preserving usability for human users.
Type
Publication
Proceedings of the ACM Web Conference 2025 (WWW ‘25)
IllusionCAPTCHA responds to the weakening of traditional CAPTCHA schemes in the LLM era by designing verification challenges around perceptual illusions rather than text recognition or simple reasoning.
