Lập Trình .NET

        public static string ToBase64(this string src, Encoding encoding)
        {
            byte[] b = encoding.GetBytes(src);
            return Convert.ToBase64String(b);
        }

        public static string Base64ToString(this string src, Encoding encoding)
        {
            byte[] b = Convert.FromBase64String(src);
            return encoding.GetString(b);
        }