Method and system for securing a data system (1) that is connected to other systems by communication means (5) and exchanges data with these other systems via said communication means. The most recently exchanged data is continuously buffered in buffer devices (2, 3). The normal operation of the data system is monitored by a monitoring device (6) that in the event of an abnormality in the operation of the data system activates an output device (7) in order to read out the buffered data from the buffer devices and to make these data available for analysis.
