METHOD TO EXECUTE A SENSITIVE COMPUTATION USING MULTIPLE DIFFERENT AND INDEPENDENT BRANCHES

The present invention relates to a method to execute by a processing unit a sensitive computation using multiple different and independent branches (SB1,SB2) each necessitating a given number of processing unit time units to be executed, characterized in that it comprises the following steps of, at each execution of a sensitive computation: - generating at least as many identifiers as the number of branches, - associating each identifier to a unique branch, - generating (S1,S2) a random permutation of identifiers, the number of occurrences of each identifier in the permutation being at least equal to the number of central processing unit time units in the shortest of the branches, - by processing (S3) each identifier in the random permutation, determining successively the branch to execute by each successive central processing unit time units according to the identifier value, - for each identifier of the random permutation, executing (S11,S21) a central processing unit time unit for the branch determined according to the identifier value.