Accessibility

SilentShield is designed to be accessible to all users, including those with disabilities. The widget targets WCAG 2.2 Level AA compliance.

Accessibility Features

• Text-to-speech — 'Read aloud' button reads the CAPTCHA question via the Web Speech API
• Keyboard navigation — full support for Tab, Shift+Tab, Enter, and Escape keys
• Screen reader support — proper ARIA labels, role='alertdialog', aria-live regions, and aria-invalid for error feedback
• Focus trap — focus stays within the CAPTCHA modal when open and returns to the previously focused element on close
• No time limit — users can take as long as needed to solve the CAPTCHA (WCAG 2.2.1)
• Reduced motion — respects the prefers-reduced-motion browser setting, all animations are disabled (WCAG 2.3.3)
• Color contrast — minimum 4.5:1 contrast ratio for all text and interactive elements (WCAG 1.4.3)

Invisible Alternative

For most users, the Proof-of-Work challenge runs invisibly in the background — no cognitive task is required at all. The visible Math CAPTCHA only appears when the invisible challenge cannot be completed. This means most users never encounter a cognitive accessibility barrier.

Language Support

The CAPTCHA interface supports 25 languages and automatically detects the user's browser language. Users can switch languages within the CAPTCHA modal via a dropdown. The language can also be set manually via the widget configuration.