/**
 *
 * 2key-ratchet
 * Copyright (c) 2016 Peculiar Ventures, Inc
 * Based on https://whispersystems.org/docs/specifications/doubleratchet/ and
 * https://whispersystems.org/docs/specifications/x3dh/ by Open Whisper Systems
 *
 */
/**
 * Crypto engine structure
 *
 * @export
 * @interface ICryptoEngine
 */
export interface ICryptoEngine {
    name: string;
    crypto: Crypto;
}
/**
 * Sets crypto engine
 *
 * @export
 * @param {string} name     Name of engine
 * @param {Crypto} crypto   WebCrypto implementation
 */
export declare function setEngine(name: string, crypto: Crypto): void;
/**
 * Returns crypto engine
 * It throws exception if engine is empty.
 *
 * @export
 * @returns {ICryptoEngine}
 */
export declare function getEngine(): ICryptoEngine;