A METHOD FOR PROTECTING A SUBSTITUTION OPERATION AGAINST A SIDE-CHANNEL ANALYSIS

摘要

The invention relates to a method for executing an operation (OP1, OP2, OPn) by a circuit (CT1), the method comprising: using a first mask set of mask parameters (u) comprising a same number of occurrences of all possible values of a word of an input data in relation with a size thereof; using an input set (PX) comprising for each mask parameter in the first mask set a data obtained by applying XOR operations to the input data and to the mask parameter; and providing an output set (PCX) comprising all data resulting from the application of the operation to a data in the input set, the output data being obtained by applying XOR operations to any of the data in the output set and to a respective second mask parameter (v) in a second mask set comprising a same number of occurrences of all possible values of the second mask parameters in relation with a size of thereof.