Encrypt and write data

		:param b: data to encrypt and write

		:return: None

def write(self, b):
		""" Encrypt and write data

		:param b: data to encrypt and write

		:return: None
		"""
		self.__buffer += bytes(b)
		bytes_written = 0
		while len(self.__buffer) >= self.__cipher_block_size:
			io.BufferedWriter.write(self, self.__cipher.encrypt_block(self.__buffer[:self.__cipher_block_size]))
			self.__buffer = self.__buffer[self.__cipher_block_size:]
			bytes_written += self.__cipher_block_size
		return len(b)