/// <summary>
    /// Base64编码及解码
    /// </summary>
    public class Base64
    {
        public static string Encode(string data)
        {
            try
            {
                byte[] dataByte = new byte[data.Length];
                dataByte = System.Text.Encoding.UTF8.GetBytes(data);
                string encodedData = Convert.ToBase64String(dataByte);
                return encodedData;
            }
            catch (Exception e)
            {

                throw new Exception(e.Message);
            }
        }

        /// <summary>
        /// 解码(UTF8)
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public static string Decode(string data)
        {
            try
            {
                byte[] outputb = Convert.FromBase64String(data);
                string result = System.Text.Encoding.UTF8.GetString(outputb);
                return result;
            }
            catch (Exception e)
            {
                throw new Exception(se.Message);
            }
        }
    }

string encodeStr = Base64.Encode("李明");
string decodeStr = Base64.Decode(encodeStr);