public string base64Encode(string inputString)
{
   try
   {
      byte[] encData_byte = new byte[inputString.Length];

      encData_byte = System.Text.Encoding.UTF8.GetBytes(inputString);  
  
      string encodedData = Convert.ToBase64String(encData_byte);

      return encodedData;
   }
   catch(Exception e)
   {
      throw new Exception("Error in base64Encode" + e.Message);
   }
}



public string base64Decode(string inputString)
{
   try
   { 
      byte[] todecode_byte = Convert.FromBase64String(inputString);

      System.Text.Decoder utf8Decoder = new System.Text.UTF8Encoding().GetDecoder();

      int charCount = utf8Decoder.GetCharCount(todecode_byte, 0, todecode_byte.Length);

      char[] decoded_char = new char[charCount];

      utf8Decoder.GetChars(todecode_byte, 0, todecode_byte.Length, decoded_char, 0);

      string result = new String(decoded_char);
      return result;
   }
   catch(Exception e)
   {
      throw new Exception("Error in base64Decode" + e.Message);
   }
}