/**
 * Convert a base64 string to an UTF-8 array
 * @param base64Str - Base64 string
 * @returns UTF-8 array
 */
export declare function base64DecToArray(base64Str: string): number[];
/**
 * Convert a UTF-8 array to string
 * @param bytes
 * @returns Decoded string
 */
export declare function UTF8ArrToStr(bytes: number[]): string;