Abstract: The present invention concerns a method for learning the parameters of a convolutional neural network, CNN, for data classification, the method comprising the implementation of steps by data processing means (11a, 11 b, 11c) of at least one server (1a, 1b, 1c), of: (a1) Learning, from a base of already-classified confidential learning data, the parameters of a first CNN; (a2) Learning, from a base of already-classified public learning data, the parameters of a last fully-connected layer (FC) of a second CNN corresponding to the first CNN to which said fully-connected layer (FC) has been added. The present invention also concerns a method for classifying an input datum.

Abstract: The present invention relates to a method for learning parameters of a convolutional neural network, CNN, for data classification, the method comprising the implementation, by means for processing data (11) of a server (1), of steps consisting of: (a1) Learning, from an already classified learning database, the parameters of a CNN, called quantized CNN, such that said parameters are valued in a discrete space; (a2) Generating a white-box implementation of at least one layer of said quantized CNN, said white-box implementation being predetermined based on at least one of said learned parameters. The present invention also relates to a method for classifying an input datum.

Abstract: The present invention comprises an enrolment method comprising steps of: acquisition (100) of an image showing a photograph itself showing an individual, extraction (102), from the image of a characteristic of the image other than a biometric model, obtaining (104) personal data of the individual other than by the image-processing algorithm, generation (106) of a reference datum (W) from the characteristic of the image and the obtained personal data, calculation (108) of an encoded datum (s) by application of an encoding procedure to the reference datum (W) and to a random datum (c), calculation (110) of a hash (h(c) of the random datum, storage (112) in a database of the datum encoded (s) in association with the hash. The invention also comprises an identity-control method using such stored data.

Abstract: 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.

Abstract: A method for processing biometric data performed by a proof entity and a verification entity; the proof entity having a biometric candidate datum, a biometric reference datum, a hash value of the biometric reference datum, a hash value of the biometric candidate datum; the verification entity having only the hash value of the biometric candidate datum; the method including steps of: generation by a data-processing unit of the proof entity of a zero-knowledge proof of the assumption that the biometric candidate datum and the biometric reference datum coincide; transmission to the verification entity of said zero-knowledge proof, the hash value of the biometric candidate datum, and the hash value of the biometric reference datum; verification by a data-processing unit of the verification entity that the zero-knowledge proof is valid, and that the hash value received from the biometric candidate datum corresponds to the one the verification entity has.

Abstract: 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.

Abstract: The present invention relates to a method for processing an image executed by a terminal (1), comprising steps of receiving a proof datum previously input by a user of the terminal (1), setting (104, 106) of at least one parameter to a first value when the proof datum is equal to a secret reference datum, and to a second value different to the first value when the proof datum is different to the secret reference datum, and generation (200) of an output datum from an input datum being or dependent on an image previously acquired by a sensor (4), and also from the parameter, the output datum having a value as function of the value the parameter has been set to.

Abstract: 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: (a) Drawing a pair formed by a first internal state (s1i) and a white-box implementation (WBi) of a modular arithmetic operation, from among a set of predetermined pairs ({(s1i,WBi)}i?[0,n-1]) each for one nonce (ki), said first internal state (s1i) being a function of the nonce (ki) and said modular arithmetic operation being a function of the first internal state (s1i), of the nonce (ki) and of the secret key (x); (b) Determining a second internal state (s2i) by application of said drawn white-box implementation (WBi) to a condensate of the document obtained via a given hash function; (c) Generating an electronic signature of the document from the first internal state (s1i) of the drawn pair and from the second determined internal state (s2i), and deleting the drawn pair of said set of pairs ({(s1i,WBi)}i?[0

Abstract: The invention relates to a method for generating a cryptographic key for applying an access control method to a resource of a server (20) by a client-terminal (10), the method comprising the following steps: (E1) receiving a test biometric datum (DBtest), (E2) applying a decoding method to the test biometric datum (DBtest) and of a reference datum (Dref) for obtaining a cryptographic key (K?) such that: if the test biometric datum (DBtest) corresponds to the reference biometric datum (DBref), the cryptographic key generated (K?) is the legitimate cryptographic authentication key (Kl), otherwise, the generated cryptographic key (K?) is an illegitimate cryptographic authentication key (Ki) not allowing authentication of the client-terminal (10) at the server (20) during an access control, and (E3) using the generated key for applying an access control method (F3) to a resource of the server (20) by the client-terminal (10).

Abstract: The present invention relates to a method for controlling the identity of a user (U), comprising the following steps implemented by an identity-controlling device (3): reading, in a public database (4), confidentiality-protected data if any previously generated by an identity-attesting device (1) from an identity element of a user (U) and at least one random datum specific to the user (U); verifying (120) heed of a condition relating to the confidentiality-protected data found in the public database (4); performing predetermined processing for the user (U) only if the condition is heeded. The public database is of blockchain type and the confidentiality-protected data generated by the identity-attesting device (1) are associated in the public database (4) with first transaction data indicating that the identity-attesting device (1) has transferred a predetermined amount of electronic currency to a recipient.

Abstract: 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 (11b) of a server (10b) of steps of: (a) Receiving said condensate and a zero-knowledge proof of the fact that said condensate is indeed the result of application of said given hash function to said document; (b) Verifying that said zero-knowledge proof is valid; (c) Generating an electronic signature of the document from said condensate.

Abstract: The invention proposes a verification process of an access right of an individual comprising conducting the following steps before the individual presents themselves at a control point, of: acquisition, by a client device, of a biometric datum on the individual, and transmission of said datum to a remote calculation server, performing a zero-knowledge calculation protocol verifiable publicly by the remote calculation server, comprising: calculation of a function comprising a remote calculation between the biometric datum and each of a plurality of reference data, comparison of each distance to a predetermined threshold, and generation of a result indicating whether at least one of the distances calculated is under said threshold, generation, from said function, of proof of exactness of calculation of the function, transmission via the remote calculation server of the result of calculation of the function and proof of exactness of the calculation to the client device, ?and the process comprises conductin

Abstract: The invention proposes a method for processing biometric data, comprising verification of the result of a calculation of distance between a biometric candidate datum and at least one biometric reference datum, each comprising a number n of indexed components (ai, bi), said calculation of distance comprising that of a polynomial of the components of the biometric data, the method being executed by a proving entity and a verification entity, the method comprising steps during which: the proving entity communicates to the verification entity the result of calculation of the distance between the candidate and reference biometric data, and said data, the proving entity generates from each datum a function of a number d of variables fa(i1, . . . , id), fb(i1, . . . , id) where d=log2 n, defined for each variable on the set {0,1}, by reformulation of the index i of each component (ai, bi) in binary format, the proving entity generates from each function a polynomial of d variables ã(x1, . . .

Abstract: The present invention concerns a method for redacting an original document consisting of a matrix of pixels each defined by a vector having at least one numerical value, the method comprising implementation by data processing means (11) of equipment (1), of steps of: (a) Determining a set of pixels of said matrix corresponding to one or more areas to be blacked-out from the original document; (b) Generating a final document corresponding to the original document in which the vectors defining the pixels of said selected set are replaced by an arbitrary vector; (c) Generating a zero-knowledge proof of the fact that the pixel matrixes of the original document and of the final document only differ via pixels belonging to said selected set. The present invention also concerns a method for verifying the authenticity of a final document.

Abstract: The invention proposes a method comprising the evaluation of a function F obtained by applying to n sub-functions fi a first operation, the evaluation comprising: the application of a series of calculation steps in which a first unit assumes a role of a client and a second unit assumes a role of a server, and the repetition of the series of calculation steps in which the roles of client and of server are exchanged between the units, each series of steps comprising: a) randomly generating, by the server, first data, and a second datum, b) for each sub-function fi, generating by the server a set of elements formed by: a result of fi evaluated in the data of the client and of the server, masked by a first datum, by applying the first operation between the result and the first datum, and masked by the second datum, by applying between the masked result and the second datum of a second operation different from the first and distributed relatively to the latter, c) recovering by oblivious transfer, by the

Abstract: The invention relates to a method for securing a document including a visual element, carried out by a processing unit comprising processing means, the method comprising generation, from the visual element, of a reference security datum, and storage of the reference security datum, wherein the reference security datum is generated by means of an algorithm configured so as to generate: for any image acquired from the visual element, a security datum whereof the differences relative to the reference security datum are less than a determined threshold, and for any image acquired on a different visual element, a security datum whereof the differences relative to the reference security datum are greater than said threshold.

Abstract: the invention proposes a method and an associated system for authenticating a user, by means of the redundancy present between several images of a video, the method using garbled circuits, named variant garbled circuits, associated with the alternative bits between the images of the video and a garbled circuit named invariant garbled circuit, associated with the invariant bits between the images of the video, so that the invariant garbled circuit only needs to be evaluated a single time.

Abstract: A method for calculating a function as a sub-function fX of a datum of a client, a sub-function fY of a datum, and a product of n indexed sub-functions fi of both data by randomly generating, n indexed invertible data ri from the set with m being a prime number, generating, for each i from 1 to n, a set for which each element is formed by a product of a datum ri with a possible result of the sub-function of two variables fi evaluated in both data, applying an oblivious transfer protocol between the client and a server so that the client recovers, for each i an intermediate datum ti equal to: ti=ri×fi(xi,Y), obtaining, by the client a result T from intermediate data such that: T=fX(X?)×?i=1nti, obtaining, by the server a result R from inverted data such that: R=fY(Y)×?i=1nri?1 using the results in a cryptographic application.

Abstract: A method for generating a message signature intended to be validated by a verifier server. A client device is configured to hold a private key and a corresponding public key. The method includes offline pre-computation by a hardware security module of a signature token, a result of encryption using a homomorphic encryption function, storage of the signature token generation of the signature of the encrypted message by the homomorphic encryption function from the result of the encryption by the homomorphic encryption function of the private key stored by the client device, of the signature token and of the message. The signature is intended to be validated by the verifier server by the public key.

Abstract: A biometric identification method of an entity including computation of a matching value between biometric data of an entity u and reference biometric data u?, by application of a function F to the biometric data. A non-interactive, publicly verifiable computation method is performed wherein representation of the function is obtained by converting an arithmetic circuit into a polynomial representation. A matching value is obtained by evaluating the arithmetic circuit and the reference biometric data as inputs. Proof of correction of the computation execution of the matching values is obtained. Verification of said received proof. The function is encoded with an integer k>1 of a vector of a biometric datum on at least one input wire of the circuit. The function includes at least m scalar products. Evaluation of the circuit is iteratively computed depending on the value of m.