METHOD FOR PROTECTING A PROGRAMMABLE CRYPTOGRAPHY CIRCUIT, AND CIRCUIT PROTECTED BY SAID METHOD

摘要

The invention relates to a circuit that comprises cells including a memory defining the logic function of each cell, integrating a differential network capable of making calculations in respect of pairs of binary variables, including a first cell network implementing logic functions on the first component of the pairs and a second network of dual cells operating in complementary logic on the second component of the pairs. A calculation step includes at least one precharge phase (41) in which the variables are placed in a known state at the input of the cells, followed by an evaluation phase (43) in which a calculation is made by the cells. A variable synchronisation phase (42, 44) is performed before the evaluation or precharge phase at each cell capable of receiving a plurality of signals conveying input variables, the synchronisation being carried out on the most delayed signal. The invention can be used for protecting this type of circuit against differential power analysis attacks.