import type { KeyStorer } from './key-store';
export interface KeyFetcher {
    fetchPublicKeys(): Promise<Array<JsonWebKeyWithKid>>;
}
interface JWKMetadata {
    keys: Array<JsonWebKeyWithKid>;
}
export declare const isJWKMetadata: (value: any) => value is JWKMetadata;
export declare const isX509Certificates: (value: any) => value is Record<string, string>;
/**
 * Class to fetch public keys from a client certificates URL.
 */
export declare class UrlKeyFetcher implements KeyFetcher {
    private readonly fetcher;
    private readonly keyStorer;
    constructor(fetcher: Fetcher, keyStorer: KeyStorer);
    /**
     * Fetches the public keys for the Google certs.
     *
     * @returns A promise fulfilled with public keys for the Google certs.
     */
    fetchPublicKeys(): Promise<Array<JsonWebKeyWithKid>>;
    private refresh;
    private retrievePublicKeys;
}
export declare const parseMaxAge: (cacheControlHeader: string | null) => number;
export interface Fetcher {
    fetch(): Promise<Response>;
}
export declare class HTTPFetcher implements Fetcher {
    private readonly clientCertUrl;
    constructor(clientCertUrl: string);
    fetch(): Promise<Response>;
}
export {};