Abstract: A device includes one or more registers and circuitry. The circuitry subjects a key having a number of bits to a first function which takes a selection value into account, generating a result having a number of bits which is twice the number of bits of the key, and stores the result in the one or more registers. In response to a call for the key, the circuitry subjects the result stored in the one or more registers to a second function which takes the selection value into account to generate a response having a same value as the key.

Abstract: A method for protecting a ciphering algorithm executing looped operations on bits of a first quantity and on a first variable initialized by a second quantity, wherein, for each bit of the first quantity, a random number is added to the state of this bit to update a second variable maintained between two thresholds.

Abstract: A first operation of comparison of the first initial operand with the second initial operand uses at least one comparison operator in such a way as to obtain a first final result word. A second operation of comparison of the second initial operand with the first initial operand uses the at least one comparison operator in such a way as to obtain a second final result word. Another operation checks the values of the bits of the two final result words in relation to a part at least of r combinations of reference values taken from possible combinations of values of these two final result words. These reference combinations represent a valid result of comparison of the two operands including an equality, a relationship of inferiority and a relationship of superiority between the two operands.

Abstract: A device includes one or more registers and circuitry. The circuitry subjects a key having a number of bits to a first function which takes a selection value into account, generating a result having a number of bits which is twice the number of bits of the key, and stores the result in the one or more registers. In response to a call for the key, the circuitry subjects the result stored in the one or more registers to a second function which takes the selection value into account to generate a response having a same value as the key.

Abstract: A method for protecting a volatile memory against a virus, wherein: rights of writing, reading, or execution are assigned to certain areas of the memory; and a first list of opcodes authorized or forbidden as a content of the areas is associated with each of these areas.

Abstract: A method of protecting a circuit from attacks aiming to discover secret data used during the execution of a cryptographic calculation by the circuit, by, executing a transformation calculation implementing a bijective transformation function, receiving as input a secret data, and supplying a transformed data, executing a cryptographic calculation receiving as input a data to process and the transformed data, and executing an inverse transformation calculation receiving as input the result of the cryptographic calculation, and supplying a result that the cryptographic calculation would have supplied if it had been applied to the data to process and directly to the secret data, the data to process belong to a stream of a multiplicity of data, the transformed data being supplied as input to the cryptographic calculation for all the data of the stream.

Abstract: A method for protecting a volatile memory against a virus, wherein: rights of writing, reading, or execution are assigned to certain areas of the memory; and a first list of opcodes authorized or forbidden as a content of the areas is associated with each of these areas.

Abstract: A method for protecting a volatile memory against a virus, wherein: rights of writing, reading, or execution are assigned to certain areas of the memory; and a first list of opcodes for which the access to the areas is authorized or forbidden is associated with each of these areas.

Abstract: A method for protecting a volatile memory against a virus, wherein: rights of writing, reading, or execution are assigned to certain areas of the memory; and a first list of opcodes authorized or forbidden as a content of the areas is associated with each of these areas.

Abstract: A method of detecting a cold-boot attack on an integrated circuit including the steps of: transferring, into a first volatile memory of the integrated circuit, a pattern stored in a non-volatile memory of the circuit; periodically causing a switching down and a switching up of the first volatile memory; and verifying that the number of bits having switched state is within a range of values.

Abstract: A method of detecting a cold-boot attack on an integrated circuit, including the steps of: periodically sampling a signal delivered by at least one ring oscillator; and verifying that the proportion of states “1” and of states “0” of the result of the sampling is within a range of values.

Abstract: A method for protecting a volatile memory against a virus, wherein: rights of writing, reading, or execution are assigned to certain areas of the memory; and a first list of opcodes authorized or forbidden as a content of the areas is associated with each of these areas.

Abstract: A method for protecting a key intended to be used by an electronic circuit in an encryption or decryption algorithm, including the steps of: submitting the key to a first function taking a selection value into account; storing all or part of the result of this function in at least two registers; when the key is called by the algorithm, reading the contents of said registers and submitting them to a second function taking into account all or part of the bits of the registers; and providing the result of the combination as an input for the algorithm, the second function being such that the provided result corresponds to the key.

Abstract: A method for protecting a calculation, by an electronic circuit, of a modular exponentiation of a digital quantity, wherein: a first variable is initialized with a random quantity increased by once unit; a second variable is initialized with the product of the digital quantity by the random quantity; a third variable is initialized with the digital quantity; iteratively for all the bits at 1 of an exponent of the modular exponentiation, the first variable is updated by: a) multiplying its content by that of the third variable; and b) subtracting thereto the content of the second variable increased by the random quantity; and once all the bits of the exponent have been processed, the content of the first variable is decreased by the random quantity to provide the result of the modular exponentiation.

Abstract: A method for protecting a ciphering algorithm executing looped operations on bits of a first quantity and on a first variable initialized by a second quantity, wherein, for each bit of the first quantity, a random number is added to the state of this bit to update a second variable maintained between two thresholds.

Abstract: A first operation of comparison of the first initial operand with the second initial operand uses at least one comparison operator in such a way as to obtain a first final result word. A second operation of comparison of the second initial operand with the first initial operand uses the at least one comparison operator in such a way as to obtain a second final result word. Another operation checks the values of the bits of the two final result words in relation to a part at least of r combinations of reference values taken from possible combinations of values of these two final result words. These reference combinations represent a valid result of comparison of the two operands including an equality, a relationship of inferiority and a relationship of superiority between the two operands.

Abstract: A method for detecting a fault injection in a random number generation circuit, wherein a bit pattern is mixed to a bit stream originating from a noise source and the presence of this pattern is detected in a signal sampled downstream of the mix.

Abstract: Authentication system comprising an input device comprising a plurality of input elements configured for inputting respectively characters in response to an input of a sequence of at least one character carried out by a user, the input device comprising at least one determination means coupled to at least one input element in order to determine a force exerted on the said at least one input element, the system comprising a recording means for recording a series of at least one force exerted on the said at least one input element, a memory configured for storing a series of at least one reference force, and comparison means configured for comparing the series of at least one exerted force with the series of at least one reference force.

Abstract: A method for protecting a calculation on an elliptic curve, by an electronic circuit, wherein a point of an elliptic curve is multiplied by a digital quantity, comprising the steps of: initializing a first variable with a value which is a function of a random quantity; initializing at least a second variable with a value which is a function of the digital quantity; at least for a bit at 1 of the digital quantity, the first variable is updated by: a) subtracting a multiple of the random quantity; and b) adding the content of the second variable; and once all the bits of the digital quantity have been processed, subtracting from the first variable the product of the point by the random quantity to provide the result.

Abstract: A method for verifying the integrity of a key implemented in a symmetrical ciphering or deciphering algorithm, including the steps of complementing to one at least the key; and verifying the coherence between two executions of the algorithm, respectively with the key and with the key complemented to one.