France Telecom

Koninklijke Philips Corporation N.v.

Orange

Olivier Billet

Henri Gilbert

Gilles Macario-Rat

Côme Berbain

Jacques Patarin

Yannick Seurin

David Arditti Modiano

Ryad Benadjila

Matt Robshaw

Stanislas Francfort

Duong Hieu Phan

A method is provided for generating a correspondence table suitable for use in a cryptographic processing method and comprising storing a plurality of input data and of output data in the table, each input datum being associated with at least one output datum in the table. For each input datum, at least one of the output data is obtained by applying a coding function to a first subsidiary datum and to an encrypted intermediate datum depending on the input datum. Also provided are a corresponding encryption method, a storage unit suitable for storing the correspondence table generated by the above generation method, a device for physically implementing such a correspondence table, a decryption device including such a storage unit, and a computer program product suitable for implementing the above generation method.

Method of generating a correspondence table for a cryptographic white box

A method and apparatus are provided to perform a cryptographic task on at least one numerical datum in an electronic hardware component. The method includes a step of at least partial use of an encryption function. This encryption function includes a basic encryption function obtained by the addition between an intermediate function arising from composition of a coding function with a first function, and a second function. This method can be applied to the encryption of a datum or to the decryption of a datum. Also, a method is provided for generating a public key and a device able to implement one of these methods.

Method for performing a cryptographic task in an electronic hardware component

A method and system for a user to obtain a derived value Kof m bits, in which, given two pseudo-random functions gand gfrom m bits to m bits, said user obtains, on the basis of an input parameter consisting of a word r of n bits, a derived value K=g&#x2218; . . . g&#x2218;g(S), where, for i=, . . . , n, g=gif r, and g=gif r, and where S is a master value of m bits which is not disclosed to said user. This method comprises the following steps: a search is conducted, from among a set of words of m bits U, where j=, . . . , p, recorded in a table Tand equal to U=g&#x2218; . . . g&#x2218;g(S), where, for i=, . . . , l(j), the indices vare predetermined bits, for a word Uequal to U=g&#x2218; . . . g&#x2218;g(S); said derived value Kis thereafter obtained by calculating K=g&#x2218; . . . g(U). Application to the encryption/decryption of pay-per-use digital contents, and to authentication.

Traceable method and system for broadcasting digital data

The invention relates to a secure communication between an electronic label (A) and a reader (B), in particular for the authentication of the label by the reader, in which: the reader () transmits at least one datum (Ch) to the label, the label calculates a combination comprising at least the datum from the reader (Ch)) and a secret (S) specific to the label, and the label communicates () the result (C(S, Ch)) of the combination to the reader (B) for verification purposes. The aforementioned combination (C(S, Ch)) is preferably calculated using a current secret value (S) delivered by a pseudo-random number generator (). The reader (B) is also provided with a homologous pseudo-random generator.

Secure communication between an electronic label and a reader

The invention relates to a method of generating a pseudorandom string of terms belonging to a finite body K of cardinal q&#x2267;2 intended to be used in a cryptography procedure, said method comprising the iterative calculation of a system (&#x393;) of m polynomials with n variables belonging to the finite body K. According to the invention, the coefficients of these m polynomials are regenerated at each iteration. The invention also relates to pseudorandom string generator intended to implement this method.

Method and a device for generating a pseudorandom string

The invention proposes a method and a device for decrypting an encrypted message represented by a sequence C or applying an electronic signature to a sequence C, said sequence C consisting of data belonging to a finite field K=GF(q), where q&#x3e;1, in which there are processed successive blocks each comprising (n&#xb7;d) successive data items from the sequence C, where n and d are predetermined integers greater than 1, the processing of such a block including the following steps: applying a predetermined affine invertible transformation tto said block; interpreting the resulting block as being formed of n successive elements (y, y, . . . , y) of an extension E=GF(q) of the field K; calculating an n-tuplet (x, x, . . . , x) of elements of the field E by solving a system f of n predetermined polynomials of the form in which the coefficients a, b, and cbelong to E and the exponents &#x3b1;, &#x3b2;, and &#x3b3;are positive or zero integers; interpreting said n-tuplet (x, x, . . . , x)as being a new block formed of (n&#xb7;d) successive elements from the field K; and applying a predetermined affine invertible transformation sto said new block.

Asymmetrical method of encryption or signature verification

A device and a method of cryptographically hashing a message M, including the following steps: forming a sequence (M, . . . , Mi, . . . , Mc) of data m-tuples M=(a, . . . , a), . . . Mi=(a, . . . , a), . . . , Mc=a, . . . , a), where m is a strictly positive integer, from said message M; iteratively calculating successive output p-tuples V, . . . , V, . . . , V, where p is a strictly positive integer, corresponding to said sequence (M, . . . , Mi, . . . , Mc) of data m-tuples as a function of at least one set of multivariate polynomials defined over a finite field; and determining a hashing value of said message M as a function of the last output p-tuple V.

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Tourrettes sur Loup, France

Olivier Billet