France Telecom

Koninklijke Philips Corporation N.v.

France Telecom Sa

Gilles Macario-Rat

Henri Gilbert

Olivier Billet

Dimitri Mouton

David Arditti

Thierry Leclercq

Vincent Barnaud

Jean-Pierre Le Rouzic

Nicolas Bugault

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 of enciphering information constituted by a finite sequence {S,S, . . . ,S} of N symbols (S,S, . . . ,S) selected from an alphabet A. There are defined both a secret convention of p key symbols K, . . . ,Kselected form a second alphabet B, and a multivariate function M having m+1 variables (m&#x3c;=N): M(X, . . . ,X,Y) operating A&#x25a1;B in A, {i, . . . ,i} being m distinct indices in the range [1,N] and the function M being bijective relative to at least one (X) of the m variables of A. A succession of X permutations are performed on the sequences {S,S, . . . ,S} such that where {S,S, . . . ,S} is the sequence prior to the jpermutation, the sequence after the jpermutation is {S,S, . . . ,S,Zj}, where Zj is equal to M(S, . . . ,S,K) the enciphered information being constituted by the sequence {S',S&#x2032;, . . . ,S&#x2032;} obtained after the Xpermutation.

Method of encipherment by permutations of fixed-length sequences

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

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Vanves, France

Gilles Macario-Rat