Idemia Identity & Security France

Emmanuel Prouff

Herve Chabanne

Hervé Chabanne

Victor Servant

Houssem Maghrebi

Guillaume Dabosville

Constance Morel

Julien Paul Keuffer

Jonathan Milgram

Olivier Clemot

Roch Olivier Lescuyer De Chaptal-Lamure

A method for digital signing of a document using a predetermined secret key. An initial internal state is determined by application to a condensate of the document of a first white box implementation of generation of a main nonce; then a modular sum of the main nonce and of a predetermined constant. The method also determines a first internal state by application to the initial internal state of a first modular arithmetic operation, then of a modular product with exponentiation of the predetermined constant. The method then determines a second internal state by application to said condensate of a second white box implementation of generation of the main nonce; and a second modular arithmetic operation function of the first internal state, of the main signature nonce and of the secret key. It then generates a digital signature of the document from the first internal state and the second internal state.

Process for digital signing of a document with a predetermined secret key

A method for secure learning of parameters of a convolution neural network, CNN, for data classification includes the implementation, by data processing of a first server, including receiving from a second server a base of already classified learning data, the learning data being homomorphically encrypted; learning in the encrypted domain, from the learning database, the parameters of a reference CNN including a non-linear layer (POLYNOMIAL) operating an at least two-degree polynomial function approximating an activation function; a batch normalization layer before each non-linear layer (POLYNOMIAL); and transmitting the learnt parameters to the second server, for decryption and use for classification.

Methods for secure learning of parameters of a convolution neural network, and for secure input data classification

The present invention relates to a method for electronic signing of a document with a predetermined secret key (x), the method being characterized in that it comprises the implementation of steps of:

Method for electronic signing of a document with a predetermined secret key

A method for encrypting or decrypting a n-tuple of data ({a}) with a n-tuple of secret keys ({k}). The method uses a data-processor to perform the steps of: (a) for each element (a), determining m&#x3e;n first internal states ({y}) by application of m first operations, each: represented by a table (T), and defined as the combination of a single bijective internal encoding (G), of a non-linear sharing function (D, E, F. . . ), and of a given non-linear permutation function (&#x192;) parameterized with the secret key (k), and (b) for each n-tuple of first internal states ({y}), determining a second internal state (z) by application of a second operation: represented by a table (T), and defined as the combination of a second single bijective internal encoding (G), a linear multiplexing function (L), and the inverses of the first bijective internal encodings (G).

Method for encrypting or decrypting a n-tuple of data with a n-tuple of predetermined secret keys

The present invention relates to a method for encryption or decryption of a data block from a secret key, wherein the method comprises: generating a first round key kdependent on the secret key, selecting each of a first mask (&#x2212;b) and a second mask (&#x2212;b) in a set consisting of a mask of bits all at one and a mask of all zero bits, calculating a first masked key k' from the first round key kand the first mask (&#x2212;b) as follows:&#x2295;(&#x2212;)wherein &#x2295; is an exclusive disjunction, executing a first encryption round applied to two first data dependent on the data block, by means of the first masked round key k&#x2032; so as to produce two second data, after producing the first masked key k&#x2032;, generating a second round key kdependent on the secret key, calculating a second masked key k&#x2032; from the second round key kand the second mask (&#x2212;b) as follows: k&#x2032;=k&#x2295;(&#x2212;b), calculating two third data L, Ras follows:&#x2295;(&#x2212;)&#x2295;(&#x2212;)&#x2295;(&#x2212;)&#x2295;(&#x2212;)and executing a second encryption round following the first encryption round, wherein the second encryption round is applied to the two third data L, Rby means of the second masked round key k&#x2032;.

Encryption/description method protected against side-channel attacks

The present invention relates to a method for symmetrical encryption or decryption of a data block from a secret key (K), the method comprising steps of:

Method for symmetric block encryption or decryption

The present invention relates to a method for generating an electronic signature of a document associated with a condensate obtained by a given hash function comprising performing by data-processing means () of a server () of steps of:

Growing community of inventors

Issy les Moulineaux, France

Emmanuel Prouff