The invention concerns a countermeasure method in an electronic component using a secret key K cryptographic algorithm with sixteen computing cycles to supply an encrypted message (C) from an input message (M), each cycle using first means TC.sub.0 to supply an output information from an input information, Said method consists in applying by selection a sequence with the first means or another sequence with other means TC.sub.1, TC.sub.2 to a group G1 comprising the first three cycles at least and another group G4 comprising the last three cycles at least. Whatever the sequence, the output result of the last cycle of each group is the same for the same input message (M).