A method for security purposes is disclosed, in which a challenge signal is applied to a physical object and a response signal is received from the physical object. The response signal comprises a plurality of characteristic resonant optical mode or a characteristic of the response signal is determined based on a spatial resolution of at least two frequency components of the response signal that is affected by luminescence effect. The inner structure of the physical structure may also comprise a network of non-linear electrical components and at least one component arranged for the reception and emission of electromagnetic radiation. The physical object may finally also be provided with electrical contact for interaction with a measuring device.     «

A method for security purposes is disclosed, in which a challenge signal is applied to a physical object and a response signal is received from the physical object. The response signal comprises a plurality of characteristic resonant optical mode or a characteristic of the response signal is determined based on a spatial resolution of at least two frequency components of the response signal that is affected by luminescence effect. The inner structure of the physical structure may also comprise a...     »