Method for detecting safety-relevant data streams, which occur in a hardware system during the execution of at least one data processing task, wherein, in order to map the hardware system onto a simulation model, the hardware system is divided into a variety of hardware components, which are connected to one another via at least one communication device and which can exchange data via this communication device, each hardware component having at least one communication unit, at least one storage unit and at least one processor unit; wherein the hardware system is mapped onto a simulation model capable of running in a simulation environment, and the data streams, occurring during the execution of a data processing task, are simulated with the simulation model of the hardware system, wherein the data streams executed by the individual hardware components are observed and logged during the simulation in the simulation environment; wherein the data streams comprise creating a copy of a datum stored at a storage address of a storage unit at another storage address of the same storage unit or a different storage unit, changing a datum or a copy of a datum, deleting a datum stored at a storage address of a storage unit, transmitting a datum from a hardware component via a communication device used by a plurality of hardware components to one or more other hardware components or transmitting and receiving data via external interfaces of the hardware system; wherein critical data are defined, which may be stored in at least one storage unit of the hardware system and/or transferred to the hardware system via an interface, characterized in that portions of the hardware system are divided into a permitted domain and a prohibited domain; in that at least the following data streams are identified as security relevant data streams: - transmitting a critical datum or instances (6', 6") thereof via a communication device of the prohibited domain - deleting a critical datum while an instance (6', 6") of the critical datum continues to exist; - creating an instance (6', 6") of a critical datum in the prohibited domain; - an continued existence of a critical datum after a certain point in time and/or system status, in particular after completion of the data processing task; and in that the creation, transmission and deletion of critical data and instances (6', 6") of critical data in the simulation model during the execution of the data processing task is monitored and the security relevant data streams are identified and logged. wherein, in order to map the hardware system onto a simulation model, the hardware system is divided into a variety of hardware components, which are connected to one another via at least one communication device and which can exchange data via this communication device, each hardware component having at least one communication unit, at least one storage unit and at least one processor unit; wherein the hardware system is mapped onto a simulation model capable of running in a simulation environment, and the data streams, occurring during the execution of a data processing task, are simulated with the simulation model of the hardware system, wherein the data streams executed by the individual hardware components are observed and logged during the simulation in the simulation environment; wherein the data streams comprise creating a copy of a datum stored at a storage address of a storage unit at another storage address of the same storage unit or a different storage unit, changing a datum or a copy of a datum, deleting a datum stored at a storage address of a storage unit, transmitting a datum from a hardware component via a communication device used by a plurality of hardware components to one or more other hardware components or transmitting and receiving data via external interfaces of the hardware system; wherein critical data are defined, which may be stored in at least one storage unit of the hardware system and/or transferred to the hardware system via an interface, characterized in that portions of the hardware system are divided into a permitted domain and a prohibited domain; in that at least the following data streams are identified as security relevant data streams: - transmitting a critical datum or instances (6', 6") thereof via a communication device of the prohibited domain - deleting a critical datum while an instance (6', 6") of the critical datum continues to exist; - creating an instance (6', 6") of a critical datum in the prohibited domain; - an continued existence of a critical datum after a certain point in time and/or system status, in particular after completion of the data processing task; - transmitting a critical datum or instances (6', 6") thereof via a communication device of the prohibited domain - deleting a critical datum while an instance (6', 6") of the critical datum continues to exist; - creating an instance (6', 6") of a critical datum in the prohibited domain; - an continued existence of a critical datum after a certain point in time and/or system status, in particular after completion of the data processing task; and in that the creation, transmission and deletion of critical data and instances (6', 6") of critical data in the simulation model during the execution of the data processing task is monitored and the security relevant data streams are identified and logged.