How to respond to DCA attacks of degree 2 or higher in table-based implementations

摘要

The present invention relates to a method for responding to a DCA attack of order 2 or higher applied to an encoded table-based (TCabi, j) implementation of a block-cipher of a cryptographic algorithm to be applied to a message m, m), applying a secret reversible encoding to obtain a set of look-up tables (TCi, j), calculating a message-independent masking value Wherein the step of calculating comprises calculating at least two shares (mmask1, mmask2) of masking values for input of the table network based on at least two different message derivation functions (F1, F2) Re-randomizing the table (TCi, j) using the calculated message independent masking values (mmask1, mmask2), calculating rounds to be applied to the message (m) based on the randomized network of the table (TCi, j) Steps to .