the like the integrated circuit may also advantageously itself form part of all sorts of optically active elements such as foils patches holograms or kinegrams which are arranged on or in the substrate as additional security features as has already been described above with regard to a security thread according to a further preferred embodiment it is also possible to shape optically active elements of this nature in such a manner that two electrically separate conductive parts of such elements function for readout and current supply both directly and capacitively the conductive parts may consist of metal conductive polymer or a combination thereof for protection purposes the integrated circuit may comprise a preprogrammed code which code is applied before the chip is incorporated in the substrate advantageously the integrated circuit comprises a code of an intrinsic property of the substrate in which the circuit is incorporated in the current state of the art the polymer ic may be used only in one direction i e it can be written or programmed once a preferred way of storing a code in the ic is to use techniques which are derived from cryptology the authentic code is then stored in the ic in an encrypted manner and deciphering is impossible without.