Thales Dis France Sas

Inside Secure

Inside Contactless

Thales Dis France Sa

Verimatrix, Inc.

Mylène Roussellet

David Vigilant

Karine Villegas

Alexandre Berzati

Vincent Verneuil

Georges Gagnerot

Benoît Feix

Benoit Feix

Steven Madec

Olivier Adjonyo Koffi Benit

Benôit Feix

Provided is a method for securing against high-order side-channel attacks wherein a substep of field inversion is performed by a cryptographic device. The method includes computing (S) a Dirac output value, adding (S) said Dirac output value to one of said shares of the first set of shares to obtain a second set of shares, performing a conversion of the second set of shares (S) from said (n+1) additive sharing to a (n+1)-multiplicative sharing, performing an inversion of each share of the (n+1)-multiplicative sharing (S), performing a conversion of the inverted shares (S) from said multiplicative sharing to a (n+1)-additive sharing to obtain a third set of shares, and adding (S) said Dirac output value to one of said shares of the third set of shares. Other embodiments disclosed.

Method for securing an AES block cipher algorithm against high-order side-channel attacks

Provided is a method for securing against side channel attacks. An elliptic curve cryptographic process comprises a multiple points multiplication operation using predetermined scalar values, Pi being points of an elliptic curve over a finite field defined by parameters (F, E, G, N) together with the point addition law where F is a field over which is defined the curve, E is an equation of the curve, G is a base point in E over F and N is the order of the base point G. The method comprises generating (S) a masking value iRand, multiplicatively masking (S) each predetermined scalar value dwith said generated masking value iRand to obtain masked scalars d', computing (S) a masked multiple points multiplication operation result, and obtaining (S) said multiple points multiplication operation result R by unmasking said masked multiple points multiplication operation result R′.

Method for securing a multiple point multiplication operation against side-channel attacks

In an aspect, a method can include generating a cyclic redundancy check code for a binary data item, using a generator polynomial; and masking, using polynomial addition, the binary data item with a binary mask. The method can also include at least one of: storing, by a microcircuit, the masked binary data item in a memory of an electronic device; or transferring, by the microcircuit, the masked data item to another device. The cyclic redundancy check code for the binary data item can be generated from the masked binary data item to prevent discovery of the binary data item by a side-channel attack during the generating the cyclic redundancy check. The binary mask can be a multiple of a random number and the generator polynomial, such that respective cyclic redundancy check code of the masked data item and the binary data item have a same result.

Cyclic redundancy check method with protection from side-channel attacks

An integrated circuit including a multiplication function configured to execute a multiplication operation of two binary words x and y including a plurality of basic multiplication steps of components xi of word x by components yj of word y is described. The multiplication function of the integrated circuit is configured to execute two successive multiplications by modifying, in a random or pseudo-random manner, an order in which the basic multiplication steps of components xi by components yj are executed.

Integrated circuit protected against horizontal side channel analysis

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Aix en Provence, France

Mylène Roussellet