/**
 * @license
 * Copyright 2022 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
import { HpkeKdf } from './hpke_kdf';
/**
 * HKDF HPKE KDF variant.
 * @see https://www.rfc-editor.org/rfc/rfc9180.html#section-4.1-3
 */
export declare class HkdfHpkeKdf implements HpkeKdf {
    private readonly hashFunction;
    constructor(hashFunction: 'SHA-256' | 'SHA-512');
    labeledExtract({ ikm, ikmLabel, suiteId, salt }: {
        ikm: Uint8Array;
        ikmLabel: string;
        suiteId: Uint8Array;
        salt?: Uint8Array;
    }): Promise<Uint8Array>;
    labeledExpand({ prk, info, infoLabel, suiteId, length }: {
        prk: Uint8Array;
        info: Uint8Array;
        infoLabel: string;
        suiteId: Uint8Array;
        length: number;
    }): Promise<Uint8Array>;
    extractAndExpand({ ikm, ikmLabel, info, infoLabel, suiteId, length, salt }: {
        ikm: Uint8Array;
        ikmLabel: string;
        info: Uint8Array;
        infoLabel: string;
        suiteId: Uint8Array;
        length: number;
        salt?: Uint8Array;
    }): Promise<Uint8Array>;
    /**
     * Copied from `javascript/subtle/hkdf`'s `compute` function
     */
    private expand;
    /**
     * Copied from `javascript/subtle/hkdf`'s `compute` function
     */
    private extract;
    getKdfId(): Uint8Array;
    getMacLength(): number;
}