Integrated circuit protecting method for e.g. chip card, involves defining function for generating sequence of values determined from secret parameter and function, and generating protection parameter in reproducible manner from sequences

摘要

The method involves generating a protection parameter (P) of secret data (K, M) by a data generator (20'), and modifying execution of a cryptographic algorithm (10) using the protection parameter. A function for generating a sequence of values is defined by successive applications at a secret parameter (S) predetermined and stored in a memory space (16) of a memory (14), where the values are determined from the secret parameter and the function. The protection parameter is generated in a reproducible manner from the sequences. An independent claim is also included for a device for protecting an integrated circuit against attacks aiming to discover secret data used during execution of a cryptographic algorithm.