Chip card with additional piezoelectric security element in which security data is stored as a sequence of polarized and unpolarized regions

Data carrier, especially a chip card, has a chip (3) for storage and processing data and an additional piezoelectric security element (5) within which additional security information is stored. The information is stored as a sequence of polarized and unpolarized regions. Independent claims are also included for the following:- (a) an external reader unit for testing the chip card with means for applying a force to the piezoelectric element and measuring the resultant voltage signal and; (b) a method for testing a chip card with a chip and a piezoelectric element. Die Erfindung betrifft einen Datenträger mit einem Chip (3) zur Speicherung und/oder Verarbeitung von Daten und mit einem piezoelektrischen Element (5). Der erfindungsgemäße Datenträger zeichnet sich dadurch aus, dass in dem piezoelektrischen Element (5) eine Information gespeichert ist.