/// <reference types="node" />
/**
 * Accessor class executes accessing to metadata service.
 *
 */
declare class Accessor {
    private static payloadData?;
    private static rootCert?;
    private static alg?;
    private constructor();
    private static createPem;
    /**
     * This method is expected to use in this class.
     *
     * @param url root certificate download endpoint
     * @returns root certificate's buffer
     */
    static _requestRootCertificate(url: URL): Promise<Buffer>;
    /**
     * Detach root certificate info.
     */
    static detachRootCert(): void;
    /**
     * Set root certificate info.
     *
     * @param pem PEM format certificate
     */
    static setRootCertPem(pem: string): void;
    /**
     * Set root certificate info.
     *
     * @param filePath DER format certificate's file path
     */
    static setRootCertFile(filePath: string): Promise<void>;
    /**
     * Set root certificate info.
     *
     * @param url certificate's URL
     */
    static setRootCertUrl(url: URL): Promise<void>;
    /**
     * Load metadata.
     *
     * @param blobJwt JWT format metadata
     */
    static fromJwt(blobJwt: string): Promise<void>;
    /**
     * Load metadata.
     *
     * @param filePath JWT format file's path
     */
    static fromFile(filePath: string): Promise<void>;
    /**
     * Load metadata.
     *
     * @param url metadata's endpoint URL
     */
    static fromUrl(url: URL): Promise<void>;
    /**
     * Return metadata payload.
     *
     * @returns metadata in JSON Object
     */
    static toJsonObject(): any;
    /**
     * Return metadata payload.
     *
     * @param filePath write metadata payload in this file
     */
    static toFile(filePath: any): Promise<void>;
    static getAlg(): string | undefined;
}
export default Accessor;