Method of testing the resistance of a circuit has an analysis by auxiliary channels

摘要

The present invention relates to a test method comprising the steps of acquisition of a plurality of sets of values (ci), each comprising the values of a physical magnitude, or of logic signals, related to the activity of a circuit to be tested (ct) during the execution of distinct cryptographic operations (oprk) applied to the same secret datum (sd), counting, for each set of values, of the number of occurrences (ht) of the values of the assembly, the calculation of a partial result (v1) of the operation for each operation, and each of the possible values (g) of a part of the secret datum, calculation of the fractions (ch) of the number of occurrences, each sum being obtained by adding the numbers of occurrences, corresponding to the operations which are applied to a same value as possible of the part of the secret datum, provide a partial result of the operation of the same value, and analysis of the sums of numbers of occurrences, in order to determine the portion of the secret datum.