/**
 * Simple in-memory cache with TTL
 *
 * For production, replace with Redis or SQLite
 */
declare class LicenseCache {
    private cache;
    private defaultTTL;
    constructor(defaultTTLSeconds?: number);
    /**
     * Generate cache key from verification request
     */
    static key(state: string, licenseNumber: string, licenseType?: string): string;
    /**
     * Get cached value
     */
    get<T>(key: string): T | null;
    /**
     * Set cached value with optional TTL
     */
    set<T>(key: string, value: T, ttlSeconds?: number): void;
    /**
     * Check if key exists and is not expired
     */
    has(key: string): boolean;
    /**
     * Delete specific key
     */
    delete(key: string): boolean;
    /**
     * Clear all cache entries
     */
    clear(): void;
    /**
     * Get cache stats
     */
    stats(): {
        size: number;
        keys: string[];
    };
    /**
     * Remove expired entries
     */
    private cleanup;
}
export declare const licenseCache: LicenseCache;
export declare const CACHE_TTL: Record<string, number>;
/**
 * Get TTL for a state
 */
export declare function getTTL(state: string): number;
export default licenseCache;
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