/**
 * Returns the credential scope which restricts the resulting signature to the specified region and service.
 *
 * @param date Current date in the format 'YYYYMMDD'.
 * @param region AWS region in which the service resides.
 * @param service Service to which the signed request is being sent.
 *
 * @returns  A string representing the credential scope with format 'YYYYMMDD/region/service/aws4_request'.
 *
 * @internal
 */
export declare const getCredentialScope: (date: string, region: string, service: string) => string;