import * as pkcs11 from "pkcs11js";
import * as core from "../core";
import * as mech from "../mech";
import { Session } from "../session";
import * as types from "../types";
/**
 * Represents digest operation
 */
export declare class Digest extends core.BaseObject {
    /**
     * Session
     */
    session: Session;
    /**
     * Creates a new instance of {@link Digest}
     * @param session Session
     * @param alg The digesting mechanism
     * @param lib PKCS#11 library
     */
    constructor(session: Session, alg: mech.MechanismType, lib: pkcs11.PKCS11);
    /**
     * Continues a multiple-part message-digesting operation operation
     * @param data Data for digest computing
     */
    update(data: types.CryptoData): void;
    /**
     * Finishes a multiple-part message-digesting operation
     * @returns Computed digest value
     */
    final(): Buffer;
    /**
     * Digests data in a single part
     * @param data Data for digest computing
     * @returns Computed digest value
     */
    once(data: types.CryptoData): Buffer;
    /**
     * Digests data in a single part
     * @param data Data for digest computing
     * @param cb Async callback function with computed digest value
     */
    once(data: types.CryptoData, cb: (error: Error, data: Buffer) => void): void;
    /**
     * Initializes a message-digesting operation
     * @param alg The digesting mechanism
     */
    protected init(alg: mech.MechanismType): void;
}