There is described a device for identifying an asset. The device comprises (a) a piece of material having predetermined physical properties, the piece of material being adapted to be irreversibly attached to the asset, (b) a stimulation and measurement unit attached to the piece of material, the stimulation and measurement unit being adapted to apply a predetermined stimulation to the piece of material and to measure a corresponding response from the piece of material, (c) an analysis unit adapted to analyze the measured response from the piece of material, and (d) a communication unit adapted to output data representative of the analysis of the measured response. There is also described an asset, an identification system and a method of identifying an asset. Furthermore, there is described a computer program.