Gesture-Based Human Verification with Blockchain: A Secure and Usable Authentication Framework

Traditional CAPTCHA mechanisms—such as dis- torted text and image selection challenges—are increasingly ineffective against modern machine learning-driven bots. This vulnerability is especially critical in decentralized applications (dApps) and Web3 platforms, where automated exploits like front-running and flash loan attacks result in substantial losses. In this work, we introduce a novel, gesture-based CAPTCHA system integrated with on-chain commit–reveal cryptographic verification and EIP-712 wallet signatures. By capturing behav- ioral nuances in user-drawn gestures and securing them through nonce-enhanced hashing and time-bound verification, our system offers two security tiers: a rapid-access ”Normal Mode” and a tamper-resistant ”Hyper-Security Mode.” Evaluations show over 97% accuracy with a low error rate (3%), minimal user abandonment (0.2%), and high satisfaction (9.3/10). This frame- work strengthens human-bot separation in trustless environments and establishes a scalable, user-friendly model for decentralized identity validation.