/**
 * Copyright (c) 2022 XYLink Inc.
 *
 * Base64 Lib
 *
 * @summary Can encode and decode string use Base64.
 * @author jinghui-Luo
 *
 * Created at     : 2022-05-10 14:53:50
 * Last modified  : 2022-05-10 15:30:01
 */
export declare const Base64: {
    _keyStr: string;
    /**
     * 使用Base64编码字符串
     *
     * @param { string } input 待编码内容
     * @returns { string }
     */
    encode: (input: any) => string;
    /**
     * 解码Base64字符串
     *
     * @param { string } input 待解码Base64字符串
     * @returns
     */
    decode: (input: any) => string;
    /**
     * private method for UTF-8 encoding
     *
     * @private
     * @param { string } string
     * @returns
     */
    _utf8_encode: (string: any) => string;
    /**
     * private method for UTF-8 decoding
     *
     * @private
     * @param {string} utfText
     * @returns
     */
    _utf8_decode: (utfText: any) => string;
};