A data-processing device includes a computing unit and an interface unit using a packet-based communication protocol, in particular PCI Express. The data-processing device also includes an intrusion detection unit that is connected via a signal connection to a filter device of the interface unit, and/or to a secure element, in the form of a Trusted Execution Environment, of an authentication arrangement related to the communication protocol. The intrusion detection unit evaluates input signals received via the signal connection for a rule infringement in a set of intrusion detection rules The filter device, at least part of which is hardware, is designed to forward only the communication data meeting an approval condition from the interface unit to an additional component of the data-processing device according to configuration information predetermined in the data-processing device and containing the approval condition. At least one intrusion detection rule relates to the infringement of the approval condition and/or to an authentication error.