import { KeyObject } from 'crypto';
import type { SignAlg } from "../types";
/**
 * Returns the digest algorithm for the given signature algorithm.
 *
 * @param   {string}  alg  The signature algorithm
 *
 * @return  {string}       The digest algorithm to be used
 */
export declare function digestAlg(alg: string): string;
/**
 * Throw an error if the key is not valid for the given algorithm.
 *
 * @param   {SignAlg}    alg  The signature algorithm
 * @param   {KeyObject}  key  The key object
 *
 * @return  {void}
 */
export declare function checkKeyType(alg: SignAlg, key: KeyObject): void;
declare const calculateSignature: (alg: SignAlg, key: KeyObject, data: Buffer) => Buffer;
export default calculateSignature;