Method and arrangement for increasing the security of circuits against unauthorized access

摘要

The invention relates to a method and an arrangement for increasing the security of circuits against unauthorized access, both of which can be used in particular to improve the security of cards, and particularly smart cards, against attacks in which the differential power analysis approach (DPA) is followed. DPA is a procedure that makes it possible to obtain not only purely functional details but also internal information stored in integrated circuits (e.g. smart-card controllers). The majority of non-clocked classes of circuit have the property that the performance of the circuit adjusts automatically to the voltage available. The invention adopts a new approach to enable integrated circuits and particularly non-clocked handshake logic to be protected against DPA. Advantage is taken in this case of a special property of self-timed logic by using a special power supply. As a result the processes in the self-timed logic take place in an unpredictable way and current consumption becomes affected by severe noise and DPA cannot be successfully applied.