| 摘要 |
<p>An identification element in the form of an integrated circuit, for example for identification cards and similar data carriers. The element contains a confidential code which is known only by the lawful owner of the card and is compared in the integrated circuit with a typed in code. To prevent the unauthorized use of the card, an independent circuit (1), which is isolated from the rest of the circuit, is provided in the element to detect incorrect code inputs and then render the card inoperable for a certain period of time. The off-period can be set as a function of the possible code permutations in such a way that it is practically impossible for the fraud to find out the correct code within the normal period of validity of the card. The circuit (2) can also be used to maintain the operability of the card for a predetermined period of time when the correct code has been typed in and without any further inputs. Thus the lawful owner has the possibility of typing in his code undisturbed by other persons before the actual use of the card.</p> |
