export declare class CTYBase64 {
    /**
    * 将字符串转为base64
    * @param value
    * @returns {string}
    */
    static ToBase64(value: string): string;
    /**
    * 将base64转为字符串
    * @param value
    * @returns {string}
    */
    static FromBase64(value: string): string;
    /**
    * private method for encoding
    * @param value
    * @returns {string}
    */
    private static encode;
    /**
    * private method for decoding
    * @param value
    * @returns {string}
    */
    private static decode;
    /**
    * private method for UTF-8 encoding
    * @param value
    * @returns {string}
    */
    private static _utf8_encode;
    /**
    * private method for UTF-8 decoding
    * @param value
    * @returns {string}
    */
    private static _utf8_decode;
}