Gemplus

Gemalto Sa

Morpho

Ingenico Group

Compagnie Industrielle Et Financiere D'ingenierie Ingenico

Jean-Sébastien Coron

David Naccache

Thomas Icart

Pascal Paillier

Eric Brier

Cédric Cardonnel

Marc Joye

Olivier Benoit

Nathalie Feyt

Jean-Louis Sarradin

Claude Barral

Christophe Clavier

Patrice Le Marre

Jean-Marie Aubanel

Medhi Tibouchi

Christophe Tymen

M David Naccache

M Eric Brier

M Patrice Le Marre

M Jean-Louis Sarradin

Mehdi Tibouchi

A cryptographic calculation includes obtaining a point P(X,Y) from a parameter t on an elliptical curve Y=f(X); and from polynomials X1(t), X2(t), X3(t) and U(t) satisfying: f(X1(t))&#xb7;f(X2(t))&#xb7;f(X3(t))=U(t)in Fq, with q=3 mod 4. Firstly a value of the parameter t is obtained. Next, the point P is determined by: (i) calculating X1=X1(t), X2=X2(t), X3=X3(t) and U=U(t); (ii) if the term f(X1)&#xb7;f(X2) is a square, then testing whether the term f(X3) is a square in Fq and if so calculating the square root of f(X3) in order to obtain the point P(X3); (iii) otherwise, testing whether the term f(X1) is a square and, if so, calculating the square root of f(X1) in order to obtain the point P(X1); (iv) otherwise, calculating the square root of f(X2) in order to obtain the point P(X2). This point P is useful in a cryptographic application.

Cryptography on an elliptical curve

There is proposed a method of generating secret and public keys vDGHV with enhanced security, implemented in a device including at least one microprocessor and a memory. The method includes generating a secret key SK corresponding the generation of a prime random number p or product of prime numbers.

Device and method for generating keys with enhanced security for fully homomorphic encryption algorithm

A method and apparatus are provided for reducing the energy consumption of an electronic terminal. The method implements a step of modifying the timeout-before-standby duration for said terminal after an action performed by and/or on said terminal at a current instant, depending on the membership of the current instant in a given temporal category, from among at least two predefined temporal categories.

Method for reducing the energy consumption of an electronic terminal by modifying timeout-before-standby duration, corresponding terminal and computer program

A cryptographic calculation includes obtaining a point P(X,Y) from a parameter t on an elliptical curve Y=f(X); and from polynomials X(t), X(t), X(t) and U(t) satisfying: f(X(t))&#xb7;f(X(t))&#xb7;f(X(t))=U(t)in Fq, with q=3 mod 4. Firstly a value of the parameter t is obtained. Next, the point P is determined by: (i) calculating X=X(t), X=X(t), X=X(t) and U=U(t); (ii) if the term f(X)&#xb7;f(X) is a square, then testing whether the term f(X) is a square in Fand if so calculating the square root of f(X) in order to obtain the point P(X); (iii) otherwise, testing whether the term f(X) is a square and, if so, calculating the square root of f(X) in order to obtain the point P(X); (iv) otherwise, calculating the square root of f(X) in order to obtain the point P(X). This point P is useful in a cryptographic application.

Cryptography on a elliptical curve

The invention relates to a method of masking a plain datum b having n bits. The inventive method is characterised in that a masked datum m is produced using the following masking function: (I), wherein p is a prime number, bis the bit at position i of plain datum b, and qis the prime number at position i in a set of prime numbers (q, . . . , q). The invention also relates to a method of masking a biometric print, consisting in: determining a set of s real minutiae which are characteristic of the print; mixing and arranging the real minutiae with t false minutiae; and forming a mixed biometric datum b having n=s+t bits, such that, for any i: b=1 if position i corresponds to a real minutia, and b=0 if position i corresponds to a false minutia. The invention can be used to secure a security document such as a bank cheque. 

Method of encrypting digital data, a method of masking a biometric print, and application to making a security document secure

In an electronic component using a secret key cryptographic algorithm, one operation utilizes a first table for supplying output data from input data. The output data, and/or derived data, is manipulated by critical instructions. A countermeasure method involves the use of other tables such that the output data and the derived data are unpredictable. The other tables are obtained from the first table by an exclusive-OR operation with a random value, or a derived random value, on one and/or the other of the input and output data of the first table.

Countermeasure method in an electronic component using a secret key cryptographic algorithm

A countermeasure method in an electronic component using a secret key algorithm K on an input message M executes an operation O(D) on input data D. A random value, of one first random information U, is generated that is of identical size as the input information D. A second random information V, is calculated by performing an exclusive OR operation between the input information and the first random information U. The operation Oor the sequence of operations are successively executed on the first input information U and to the second random information V, supplying respectively a first random result O(U) and a second random result O(V).

Method for countermeasure in an electronic component using a secret key algorithm

A method and associated device for checking a biometric signature by a simple and secure calculation adapted to personal objects of the chip card type. The method is based on the storage within the object of an obscured biometric signature and an associated authentication code. A terminal capturing a fingerprint compares the fingerprint data with the obscured biometric signature transmitted by the card and transfers the result of this comparison to the chip card, which validates this result with the authentication code.

Biometric identification method and device adapted to verification on chip cards

There exist numerous public key probabilistic encryption algorithms. Most of these algorithms do not have a maximum security level against someone capable of chosen ciphertext attacks. The disclosed method provides a construct to enhance the security of any public key probabilistic or deterministic encryption algorithm to achieve an optimal security level.

Method for enhancing security of public key encryption schemas

A countermeasure method in an electronic component implementing an elliptical curve based public key cryptography algorithm. A new decryption integer d' is calculated such that the decryption of an encrypted message on the basis of a private key d and the number of points n of an elliptical curve provides the same result with d&#x2032; as with d, by performing the operation Q=d*P, whereby P is a point of the curve. Four steps are employed in the calculation:) a security parameter s is determined,) a random number k ranging from 0-2is drawn,) the integer d&#x2032;=d+k*n is calculated, and) Q=d&#x2032;.P is calculated.

Countermeasure method in an electric component implementing an elliptical curve type public key cryptography algorithm

A cryptography method for generating probabilistic digital signatures and/or for a key-exchange a protocol and/or for an encryption algorithm is based on the use of a public key algorithm on abnormal binary elliptic curve, such as a Koblitz curve. A point P (x, y) is selected, and pairs (k, P) are stored with Pbeing the point corresponding to the scalar multiplication of the point P by k. A random variable (k) is generated and a point C is calculated that corresponds to the scalar multiplication of P by k. The generation of the random variable (k) and the calculation of the point C are performed simultaneously.

Cryptography method on elliptic curves

Elliptical curve based cryptographic algorithms are public key algorithms offering a shorter calculation time and smaller key sizes in comparison with RSA. In a smart card type environment, these algorithms are vulnerable to differential power analysis (DPA) attacks. The disclosed invention provides a countermeasure procedure enabling positive action to be taken against DPA-type attacks. The countermeasure does not reduce performance and is easy to use in a smartcard type component.

Countermeasure procedures in an electronic component implementing an elliptical curve type public key encryption algorithm

Two methods for random number generation are modified to make them more resistant to attacks by current measurements. The methods are particularly designed to be implemented in electronic devices such as smart cards, PCMCIA, badges, contactless cards or any other portable device. The DES algorithm is encrypted using a key K having a value D representing date information, to generate an integer variable I. For j ranging from 1 to m, the following steps are carried out: substituting s with s XOR I; introducing in the integer variable y the result of the encryption of s with the DES algorithm using the key K; introducing in xthe result of y or s; substituting s with y XOR I; and introducing in s the result of the encryption of s with the DES algorithm using the key K. The sequence (x, x, x) is then restored in the output.

Method for improving a random number generator to make it more resistant against attacks by current measuring

A countermeasure method in an electronic component which uses an RSA-type public key cryptographic algorithm. A first countermeasure method uses a random calculation for each new execution of the decryption algorithm with CRT. The calculations are made modulo p*r and q*t, r and t being random numbers. A second countermeasure makes the recombination random using the CRT theorem.

Countermeasure method in an electronic component which uses an RSA-type public key cryptographic algorithm

The invention concerns a method for testing sources generating random numbers, particularly sources set up in the context of cryptographic systems such as random number generators incorporated in chip cards. The invention is particularly designed to be used for testing and validating electronic devices such as chip cards, PCMCIA, badges, contactless cards or any other similar portable apparatus.

Growing community of inventors

Paris, France

Jean-Sébastien Coron