code: def _ReadEncryptedData(self, read_size):
      
      encrypted_data = self._file_object.read(read_size)
  
      read_count = len(encrypted_data)
  
      self._encrypted_data = b''.join([self._encrypted_data, encrypted_data])
  
      self._decrypted_data, self._encrypted_data = (
          self._decrypter.Decrypt(self._encrypted_data))
  
      self._decrypted_data_size = len(self._decrypted_data)
  
      return read_count
docs: Reads encrypted data from the file-like object.
  
      Args:
        read_size (int): number of bytes of encrypted data to read.
  
      Returns:
        int: number of bytes of encrypted data read.