France Telecom

France Telecom Establissement Autonome De Droit Public

France Telecom Sa

David Arditti

Mireille Campana

Henri Gilbert

Marc Girault

Jean-Claude Pailles

Dimitri Mouton

Jacques Stern

Thierry Leclercq

Gilles Macario-Rat

Sophie Milano

Olivier Clemot

Nicolas Bontron

Laurent Stoffel

Olivier Boulot

Nicolas Bugault

David Pointcheval

Jean Millot

Jacques Burger

Francois Allegre

The present invention relates to a cryptographic method of protecting an electronic chip against fraud and a device including an electronic chip which is adapted to protect the electronic chip against fraud. The method includes: mixing some or all of the input parameters (E) to supply an output data item E'=(e&#x2032;, e&#x2032;, . . . , e&#x2032;, . . . , e&#x2032;), changing the state of a finite state automaton from an old state to a new state as a function of the data item E&#x2032;=(e&#x2032;, e&#x2032;, . . . , e&#x2032;, . . . , e&#x2032;), and calculating a certificate (S) by means of an output function having at least one state of the automaton as an input argument. The device includes: mixing means, a finite state automaton, and output means for calculating a certificate (S).

Cryptographic method of protecting an electronic chip against fraud

In order to prevent the use of a virtual prepaid card illegitimately acquired and transmitting only one identification code, for example read after the card has been scratched, to a service provision server, a second code is delivered on paying for the card, and the two codes have to be authenticated so that the user-purchaser of the card can subsequently use the service concerned in the server still using only the first code.

Service activation by virtual prepaid card

This invention relates to an authentication process with an access control and/or payment system that maintains anonymity of the customer towards a third party, characterized in that a single-directional authentication protocol is used to send an authentication sequence that is completely different for each transaction, so that it is impossible for a third party to determine the identity of this customer, or even to determine which transactions are sent by a particular customer.

Authenticating method for an access and/or payment control system

Method for controlling independent secure transactions by means of a single apparatus

A process for the identification of a claimant by a verifier. The process is of the public key type, where the public exponent is equal to 3. The claimant draws at random a first exponent .alpha., calculates r=g.sup..alpha. mod n and transmits R=r.sup.3. The verifier draws at random a second exponent .beta., calculates t=g.sup..beta. mod n, calculates T=t.sup.3 mod n and h=H.sub.1 (Z), where H.sub.1 is a hash function, and calculates Z=R.sup.3 mod n. The verifier transmits to the claimant the numbers T and h. The claimant calculates Y=T.sup..alpha. mod n, verifies the result H.sub.1 (Y), calculates H=H.sub.2 (Y), where H.sub.2 is another hash function, calculates z=rS mod n, and transmits z and H. The claimant also has a secret number S equal to the modulo n cubic root of a number I deduced from its identity so that the number S verifies S.sup.3 =I mod n. The verifier verifies that H received is equal to H.sub.2 (Z) and that z.sup.3 is equal to RI mod n.

Public key identification process using two hash functions

The present invention relates to a process for accepting a request for use of a virtual prepaid card involving the following stages:

Process for the acceptance of a virtual prepaid card use request

A process for the dissimulation of concealment of a secret code in a data authentication device by encrypting the secret code by an encrypting function for forming an image of the secret code and storing the secret code image in the authentication device. Beforehand, an encrypting function is chosen such that with each stored secret code image corresponds a plurality of antecedent codes all differing from the secret code, but which, once encrypted by the encrypting function have an image identical to that of the secret code. The secret code of a user has an authentication device in which is stored the secret code image.

Process for the dissimulaton of a secret code in a data authentication

A cryptographic process is for protection against fraud. An allocation of a secret key K is made to a card and to an application and an input value R is defined. The card and application calculate the modulo 2 scalar product of binary vectors constituted by words of R and words of K. The application checks whether the result obtained by the card is in agreement with its own result. An exemplary application is low cost cards.

Cryptographic process for protection against fraud

A process for controlling communication between a first and a second smart card using key-based cryptography is provided. In the disclosed process, a first identity code is stored in the first smart card and a second identity code is stored in the second smart card. The smart cards are customized by writing into each of the smart cards an identical group secret key and respective algorithms for processing the identical group secret key and the first and second identity codes stored in the first and second smart cards, respectively. The smart cards are used by transmitting the first identity code to the second smart card, transmitting the second identity code to the first smart card, and calculating using the respective processing algorithms stored in the smart cards, first and second session keys for the first and second smart cards, respectively.

Process for the control of secret keys between two smart cards

A process is provided for authentication in a data processing system using a data processing terminal having a programmable memory. The terminal supplies to a server an identify code (ID), the server checks the identify code, and in the case of agreement, supplies a random number (ALEA-A) to the terminal. The terminal encodes the random number using a signature algorithm (B) defined by a secret key (SID), and supplies a first signed random number (ALEA-S) to the server, which applies a signature checking algorithm (T, B, C) to the number (ALEA-S). The identity code and an encrypted secret key (KID) are written into the memory. The secret key (SID) used for the signature of the random number is determined using a decrypting algorithm (INVA) using the encrypted secret key (KID) and a password (MP) supplied by the terminal user. Particular utility for the present invention is found in the area of data processing, although other utilities are also contemplated.

Process for the authentication of a data processing system by another

An electronic device for processing digital data has an input for receiving data to be processed and processor means suitable for transforming the input data in non-falsifiable manner into a result condensed data block. The processor means tools that are simple and fast, such as arrays and logic operators, to provide an elementary anti-collision operation for use in condensing the digital data.

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Clamart, France

David Arditti