code: def encrypt_template(self, enc_key, mac_key, enc_offset):
          
  
          # AES-256-CBC/PKCS7Padding
          to_encrypt = self.tpl_buff[enc_offset:]
          encrypted = aes_enc(enc_key, PKCS7.pad(to_encrypt))
  
          # Mac the whole buffer
          to_mac = PKCS7.pad(self.tpl_buff[:enc_offset] + encrypted)
          mac = cbc_mac(mac_key, to_mac)
  
          return to_mac + mac
docs: Encrypts current tpl_buf according to the protocol - symmetric encryption
          :param enc_key:
          :param mac_key:
          :param enc_offset:
          :return: