A system has at least one machine, including at least one device for exchanging data with another device of the at least one machine or of another machine for a joint solution of a task or with a higher-level device. The system further including a certification device configured to identify the at least one machine with a root certificate and configured to grant a sub-certificate to the at least one device of the machine. The certification device is further configured to sign the sub-certificate with the root certificate of the at least one machine in order to identify the at least one device as belonging to the at least one machine, and the sub-certificate is issued biuniquely for the at least one device.