摘要 |
The verifying system for an identity or credit card has a mechanism for detecting irregularities (11) in the structure or surface of the material from which the card (10) is made. The detected irregularities (11) are converted into a pulse signal. The pulses are combined with clock pulses, and the combined pulses converted into a binary code. This binary code is compared with a stored binary code, obtained from a reference scan of the card (10). A control function, e.g. the release of an access gate, or the return of the card, is performed in response to agreement between the two codes. |