CAPTCHA

A challenge-response test used on websites to determine whether a user is human, typically requiring users to identify distorted text, select images, or solve puzzles. CAPTCHAs present significant accessibility barriers, particularly for users with visual impairments who cannot interpret image-based challenges, and for users with cognitive disabilities who may struggle with complex puzzles. Audio CAPTCHA alternatives are often difficult to comprehend, and time-limited challenges can exclude users who interact more slowly with assistive technologies. The W3C has documented these barriers extensively and recommends alternative verification methods where possible.