METHOD FOR COUNTERMEASURE IN AN ELECTRONIC COMPONENT USING A SECRET KEY ALGORITHM

摘要

The invention concerns a countermeasure method in an electronic component using a secret key algorithm K on an input message M characterised in that the execution of an operation OPN or of a sequence of operations comprising manipulating bit by bit an input information D, to supply an output information OPN(D), comprises the following steps: drawing a random value, of one first random information U, of identical size as the input information D; calculating s second random information V, by performing an exclusive OR between the input information and the firs random information U; executing the operation OPN or the sequence of operations successively to the first input information U and to the second random information V, supplying respectively a first random result OPN(U) and a second random result OPN(V).