Inside Secure

Gemalto Sa

Inside Contactless

Benoit Feix

Georges Gagnerot

Vincent Verneuil

Mylène Roussellet

Bruno Benteo

Sebastien Nerot

Mylene Roussellet

Mathieu Ciet

The invention relates to a method for personalizing a secure processor in a NFC system to execute a secure application, comprising steps of obtaining by a server identification data of a user memorized in a secure storage medium, personalization data corresponding to the user identification data, and identification data of a NFC system of the user, comprising an encryption key of the secure processor, encrypting by the server personalization data using the encryption key, transmitting to the NFC system encrypted personalization data, receiving by the secure processor encrypted personalization data, deciphering personalization data, and memorizing in a secured way personalization data by the secure processor.

Method of personalizing a NFC chipset

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

A process for testing an integrated circuit includes collecting a set of points of a physical property while the integrated circuit is executing a multiplication, dividing the set of points into a plurality subsets of lateral points, calculating an estimation of the value of the physical property for each subset, and applying to the subset of lateral points a step of horizontal transversal statistical processing by using the estimations of the value of the physical property, to verify a hypothesis about the variables manipulated by the integrated circuit.

Process for testing the resistance of an integrated circuit to a side channel analysis

A cryptographic method carries out a modular exponentiation of the type C=A&#x3c;B1&#x3e; mod N, where A is an operand, B1 is a first exponent, N is a modulus and C is a result. The method includes the steps of masking the operand A by a number s, carrying out a modular exponentiation of the masked operand by the exponent B1, and demasking the result of the exponentiation, by removing a contribution from the random number s from the result of the exponentiation. During the step of masking the operand A, the operand A is multiplied by a parameter of the form K&#x3c;s.B2&#x3e;, where K is a constant and B2 is a second exponent such that B1.B2=1 mod N. The method is implemented preferably by using a Montgomery multiplier. The preferred choice for the constant K is K=2, p being an integer lying between 0 and n, n being an upper bound of the size of the modulus N and conventionally depending on the choice of implementation of the Montgomery multiplication.

Cryptographic method comprising secure modular exponentiation against hidden-channel attacks, cryptoprocessor for implementing the method and associated chip card

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La Ciotat, France

Benoit Feix