HAPTCHA: Eyes-Free Haptic CAPTCHA in Mobile Environments: Design Principle, Security Evaluation, and User Experience
Year: 2026
Type: conference-paper
Abstract: Traditional visual CAPTCHAs face dual challenges: increasing vulnerability to automated solvers and maintaining usability without imposing excessive visual burden. We propose Haptic CAPTCHA (HAPTCHA), an eyes-free human-verification framework that leverages smartphone vibration as the primary information channel. HAPTCHA grounds security in a human closed-loop sensorimotor process that is inherently difficult for automated agents to emulate. We instantiate this framework through two complementary designs: tiltHAPTCHA, an efficiency-oriented spatial search task, and rhythmHAPTCHA, a robustness-oriented temporal reproduction task. Our security analysis against sophisticated imitation-learning bots shows that HAPTCHA’s structured interaction traces provide a robust signal for discrimination, achieving up to 100% bot rejection rate in unseen attack scenarios. The usability evaluation across sitting, walking, and fast-walking scenarios demonstrates that HAPTCHA maintains high solvability (e.g., 96.7% success rate for tiltHAPTCHA while sitting) and offers superior usability with significantly lower cognitive workload than a visual reCAPTCHA mockup. These findings position HAPTCHA as an explicit haptic challenge layer that complements passive, risk-based verification by moving challenge information beyond the screen.
Institution: Pohang University of Science and Technology
Language: English
Subfield: Information Systems
Field: Computer Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7225014624