Patent ID: 8199909
Filing Date: 2012-06-12
Classification: H04L

Abstract:
1. A method for carrying out a cryptographic calculation in an electronic component, wherein a determined cryptographic calculation carried out in the electronic component includes at least one nonlinear operation specified on data blocks of k bits, k being an integer greater than 2, the method comprising the step of protecting the electronic component from attacks based on information leaked by the electronic component during execution of the cryptographic calculation by the electronic component, by: generating, in the electronic component, several masked intermediate data blocks of j bits from an initial data block of k bits, j being an integer smaller than k; computing, in the electronic component, a masked product of two intermediate data blocks of j bits by: applying, in the electronic component, a nonlinear operation S specified on data blocks of j bits, corresponding to said nonlinear operation specified on data block of k bits, to at least one of the masked intermediate data blocks of j bits by means of a substitution table with 2 combining, in the electronic component, the modified data block of j bits and at least certain of said masked intermediate data blocks of j bits into a result block of k bits corresponding to the initial data block of k bits through a transformation including said nonlinear operation specified on data blocks of k bits.