Low-complexity electronic circuit protected by customized masking

摘要

A cryptography circuit protected by masking, said circuit including means for encrypting binary words using at least one key krc, means for applying linear processing operations and nonlinear processing operations to said words and means for masking said words. The binary words are unmasked upstream of the nonlinear processing operations by using a mask kri and masked downstream of said processing operations by using a mask kr+1i, the masks kri and kr+1i being chosen from a set of masks that is specific to each instance of the circuit.

主权项

1. A cryptography circuit protected by masking, said cryptography circuit comprising:
means for encrypting a plurality of binary words using at least one key krc; means for applying linear processing operations and nonlinear processing operations to said plurality of binary words; and means for masking said plurality of binary words, wherein the plurality of binary words are unmasked upstream of the nonlinear processing operations by using respective masks kri and masked downstream of the nonlinear processing operations by using respective masks kr+1i, the masks kri and kr+1i forming part of a set of masks specific to each instance of the cryptography circuit, wherein each said mask kri is a secondary mask deduced from primary masks ki such that kr+1i=P(kri) and k0i=ki, the function P(x) corresponding to a function for permutating elements of x, and wherein the primary masks ki are composed of an integer number greater than one of submasks of a same length, the secondary masks kri being generated by permutation of said submasks.