Side channel attack prevention in data processing apparatus such as a smart card

摘要

Data processing apparatus is provided which comprises: a processor (5); memory (3); a scrambler (110) arranged on a data transfer path (114) between the processor (5) and the memory (3), for scrambling data items passing through the scrambler (110) according to a specified scrambling regime; and at least one designated control line (120) arranged between the processor (5) and the scrambler (110) for switching the scrambler (110) at least between operating according to a first scrambling regime and operating according to a second scrambling regime different to the first scrambling regime. The data processing apparatus is a smart card in the embodiment.