Oberthur Technologies

Idemia France

Other

Idema France

Oberthur Card Systems Sa

Christophe Giraud

Alberto Battistello

Hugues Thiebeauld De La Crouee

Olivier Chamley

Nicolas Morin

Laurie Genelle

Luk Bettale

Guillaume Dabosville

Guillaume Barbu

Emmanuelle Dottax

Franck Rondepierre

Nicolas Debande

Arnaud Boscher

Nicolas Bousquet

Paul Dischamp

Emmanuel Prouff

Jean-Bernard Fischer

Vincent Verneuil

Robert Naciri

Nathan Reboud

Thomas Chabrier

Gregoire Godel

Philippe Andouard

Alberto Batistello

Soline Renner

Antoine Lemarechal

Régis Bevan

Clémence Vermeersch

Rina Zeitoun

Agathe Houzelot

Laurent Castelnovi

Sarah Lopez

Grégoire Godel

A method for cryptographic signature of a datum comprises determining: a signature point equal to the addition of elements equal to a derived first point and of number equal to a first scalar; a second scalar by subtracting, from the product of the first scalar and of a selected scalar, the product of a third and of a fourth scalar; another signature point equal to the addition of elements equal to a selected point and of number equal to the second scalar, and of elements equal to a derived second point and of number equal to the fourth scalar; and a signature portion based on a private key, on the first scalar, on a coordinate of the signature point and on the datum. The derived first and second point are respectively equal to the addition of elements equal to a generator point and of number equal to a fifth and to the third scalar.

Method for cryptographic signature of a datum, associated electronic device and associated computer program

The invention proposes a novel type of infective countermeasure against fault injection attacks. Instead of determining the injected error before amplifying it, the novel countermeasure applies the same diffusion function to two intermediate ciphers obtained by executing a cryptographic operation on an input. The error is therefore amplified within the same intermediate ciphers, referred to as infective ciphers after diffusion. It is then possible to use diffusion functions which do not map the cipher 0 as an output equal to 0. A cipher recomposed from bits of undiffused ciphers is also generated. These infective and recomposed ciphers are XOR-combined to provide an output cipher. This approach makes it possible to adapt, by simple duplication of the pairs and associated specific diffusion functions, the protection offered by the countermeasure to a desired number of injected faults.

Infective countermeasures

A cryptographic processing method comprises the following steps:

Cryptographic processing method, related electronic device and computer program

Disclosed is a method of verifying integrity of a pair of public and private cryptographic keys within the additive group of the integers modulo N, with N being the product of two primary numbers p and q, the method including: calculating a candidate private exponent d' corresponding to a private exponent d of the private key; and executing a test of integrity. The test of integrity includes a step for verifying the coherence of the candidate private exponent d&#x2032; with respect to a public exponent e of the public key and to the numbers p and q, the verification step involving a first multiple modulo of the public exponent e of the public key and a second multiple modulo of the public exponent e of the public key.

Method of verifying integrity of a pair of cryptographic keys and cryptographic device

A cryptographic method is provided. The cryptographic method comprises an initialisation phase for determining a provisional generator point G' equal to a first product G&#x2032;=[d&#x2032;]G, where d&#x2032; is a first random scalar forming a secret key of N bits and G is a generator point of an elliptical curve, and determining a provisional key Q&#x2032; equal to a second product Q&#x2032;=[d&#x2032;]Q, where Q is a point of the elliptical curve forming a public key. During an encryption phase a second random scalar forming a second secret key k of M bits, with M&#x3c;N; a public key P is calculated such that P=[k]G&#x2032;; a coordinate of an intermediate point SP, of the elliptical curve, equal to a fourth product SP=[k]Q&#x2032;; at least one key by application of a derivation function (F); and data (T) are encrypted based on said at least one key.

Cryptographic processing events for encrypting or decrypting data

A method of executing a program by a processor, and an electronic entity including such a processor, the method includes the following steps:

Method of executing a program by a processor and electronic entity comprising such a processor

Devices and methods for masking and unmasking sensitive data, based on a standard cryptographic algorithm defining a ciphering algorithm, and a deciphering algorithm using more resources than the ciphering algorithm are described. The masking of sensitive data is done by applying the deciphering algorithm to the sensitive data to obtain masked sensitive data. The unmasking of the masked sensitive data is done by applying the ciphering algorithm to the masked sensitive data to obtain sensitive data in plain form.

Masking and unmasking methods and devices

Generation of a message m of order &#x3bb;(n) for a test of the integrity of the generation of a pair of cryptographic keys within the multiplicative group of integers modulo n=p&#xb7;q, including: &#x2014;key pair generation including, to generate p and q: a random selection of candidate integers; and a primality test; &#x2014;a first search of the multiplicative group of integers modulo p for a generator a; &#x2014;a second search of the multiplicative group of integers modulo q for a generator b; &#x2014;a third search for a number y, as message m, verifying: 1&#x2264;&#x3b3;&#x2264;n&#x2212;1, where &#x3b3;=a mod p and &#x3b3;=b mod q, the first or second search being performed during the primality test.

Message generation for a cryptographic key generation test

A secure element includes a boot program comprises instructions for the execution a startup step to determine if a non-volatile memory stores an active operating system, and, in the affirmative, to launch execution of the operating system, an authentication step of a updater device, as a function of first authentication data determined by a secure element and second authentication data received from the updater device, and, in response to the authentication step, a storage step of a new operating system received from the update, device in the non-volatile memory and an activation step of the new operating system, when said instructions are executed by a microprocessor.

System and method for updating an operating system for a smart card or other secure element

Method for generating a pair of public and private cryptographic keys in the additive group of integers modulo n, where n is the product of two prime numbers p and q, the method including the following steps:

Generation of cryptographic keys

Method of integrity verification of cryptographic key pairs, the method including an integrity test with:

Integrity verification of cryptographic key pairs

Method of integrity verification of public and private cryptographic key pairs in the additive group of integers modulo n, with n being the product of two prime numbers p and q, the method including the following steps:

A smart card reader capable of transmitting a power signal to a smart card to determine a duration WT called Waiting Time in keeping with the standard ISO 7816 and sending commands to the smart card, the reader comprising a detector for detecting a malfunctioning condition of the smart card and being configured to cut the power signal when the malfunctioning condition is fulfilled. This reader is remarkable in that the malfunctioning condition is different to reaching, by a counter configured to be incremented with the time from the sending of a command to the smart card, of a value corresponding to the duration WT elapsed from the sending of the command or reinitialization of the counter in response to the receipt of a protocol message of the smart card.

Smart card reader

A method of cryptographic processing of data (X), in particular a method protected against fault injection attacks, and an associated device. The processing includes at least one transformation (-) of an input data item (s) into a result data item (s'). In this case the method includes a step (E) of verifying the transformation including the following steps:

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Colombes, France

Christophe Giraud