/**
 * Browser Fingerprinting Utility
 * Generates a deterministic fingerprint based on stable browser/hardware characteristics.
 * Used for demo link usage limit tracking.
 *
 * Strategy:
 *   1. localStorage persistence — generate once, reuse across tabs/sessions forever
 *   2. Stable hardware-only seed — if storage is cleared, the same hardware signals
 *      produce the same hash, so the fingerprint stays consistent
 *   3. Server-side IP fallback — handled by the backend when no fingerprint is sent
 */
export declare class BrowserFingerprint {
    private static cachedFingerprint;
    /**
     * Generate (or retrieve) a deterministic browser fingerprint.
     * Cached in memory → localStorage → derived from stable hardware signals.
     */
    static generate(): Promise<string>;
    /**
     * Collect only hardware / environment signals that do NOT change between
     * tabs, sessions, or browser restarts on the same device.
     *
     * Deliberately excluded (volatile / anti-fingerprint randomised):
     *   - canvas.toDataURL()  — randomised per origin in many browsers
     *   - font detection       — noisy across rendering states
     *   - screen.availWidth/Height — changes with taskbar / dock resize
     *   - navigator.doNotTrack — user can toggle
     *   - timezoneOffset       — changes with DST
     *   - navigator.userAgent  — changes on browser update
     */
    private static getStableSignals;
    /**
     * WebGL vendor + renderer string (GPU identifier, very stable)
     */
    private static getWebGLFingerprint;
    /**
     * SHA-256 hash of the signals object → hex string
     */
    private static hashComponents;
    private static getStored;
    private static persist;
    /**
     * Clear both in-memory and persisted fingerprint (useful for testing)
     */
    static clearCache(): void;
}