Abstract: A method encrypts, using an encryption circuit, a first data value having a number n of first binary words, each word having a number m of bits. The encrypting includes generating a second data value having a same number n of second binary words of m bits each and outputting a result of the encryption. The number n is an integer greater than or equal to 3, m and n do not have a common integer division, and n or m is even. A second binary word of the second data value having a rank i is equal to a sum of: a first binary word having a same rank i; and a product of: a complement of a first binary word having rank ((i+1)modulo n), shifted by a first number of bit positions; and a first binary word having rank ((i+2)modulo n), shifted by a second number of bit positions.

Abstract: The disclosure concerns an encryption function applied to a first word, a second word, a third word, and a fourth word including: multiplying the third word by the fourth word; adding the result of the multiplication; subtracting the result of the addition to the second word from the result of the addition to the first word; adding the result of the subtraction; combining with a constant the result of the addition of the third word to the result of the subtraction; and multiplying by two the result of said combination and circularly shifting the codes of the respective results of the addition of the fourth word to the result of the subtraction, of the addition of the second word to the result of the multiplication, and of the addition of the first word to the result of the multiplication.

Abstract: A method encrypts, using an encryption circuit, a first data value having a number n of first binary words, each word having a number m of bits. The encrypting includes generating a second data value having a same number n of second binary words of m bits each and outputting a result of the encryption. The number n is an integer greater than or equal to 3, m and n do not have a common integer division, and n or m is even. A second binary word of the second data value having a rank i is equal to a sum of: a first binary word having a same rank i; and a product of: a complement of a first binary word having rank ((i+1)modulo n), shifted by a first number of bit positions; and a first binary word having rank ((i+2)modulo n), shifted by a second number of bit positions.

Abstract: The disclosure concerns an encryption function applied to a first word, a second word, a third word, and a fourth word including: multiplying the third word by the fourth word; adding the result of the multiplication; subtracting the result of the addition to the second word from the result of the addition to the first word; adding the result of the subtraction; combining with a constant the result of the addition of the third word to the result of the subtraction; and multiplying by two the result of said combination and circularly shifting the codes of the respective results of the addition of the fourth word to the result of the subtraction, of the addition of the second word to the result of the multiplication, and of the addition of the first word to the result of the multiplication.

Abstract: A method of performing a cryptographic operation including: receiving a plurality of binary input values; splitting the binary input values into a plurality of non-binary digits of base r, where r is an integer greater than 2 and not equal to a power of 2; and performing, by a cryptographic block on each of the plurality of non-binary digits, a different modulo r operation to generate at least one output digit) of base r.

Abstract: A method of derivation, by an electronic circuit, of a first key from a second key, wherein: at least one third key is derived from the second key and is used to derive the first key; and a value of a counter, representative of the number of first keys, conditions the derivation of a new value of the third key.

Abstract: A method for protecting a generation, by an electronic circuit, of at least one prime number by testing the prime character of successive candidate numbers, including: for each candidate number: the calculation of a reference number involving at least one first random number, and at least one primality test based on modular exponentiation calculations; and for a candidate number having successfully passed the primality test: a test of consistency between the candidate number and its reference number.

Abstract: A method of derivation, by an electronic circuit, of a first key from a second key, wherein: at least one third key is derived from the second key and is used to derive the first key; and a value of a counter, representative of the number of first keys, conditions the derivation of a new value of the third key.

Abstract: A method and a system for personalizing electronic elements, by replacing, in a non-volatile memory of each of the electronic elements a first secret key with a second secret key, by a secure authentication module automatically generating the second key after having restored the first one from an identifier of the element being personalized, including conditioning, on the authentication module side, the provision of the second key to a current element to the reception of a message confirming the key replacement of at least one preceding element.

Abstract: A method of performing a cryptographic operation including: receiving a plurality of binary input values; splitting the binary input values into a plurality of non-binary digits of base r, where r is an integer greater than 2 and not equal to a power of 2; and performing, by a cryptographic block on each of the plurality of non-binary digits, a different modulo r operation to generate at least one output digit) of base r.

Abstract: A method and an element of ciphering by an integrated processor of data to be stored in a memory, including applying a ciphering algorithm which is a function of a key specific to the integrated circuit and of an initialization vector, and of memorizing at least the ciphered data, the initialization vector depending at least on the address of storage of the data in the memory.

Abstract: A method and device for encrypting and/or decrypting binary data blocks protecting both confidentiality and integrity of data sent to or received from a memory. The encryption method comprises steps of: applying to the input data block a reversible scrambling process, the scrambling process providing a scrambled data block in which the bits of the input data block are mixed so that a modification of one bit in the scrambled data block impacts on every bit of the input data block, and applying to the scrambled data block a stream cipher encryption algorithm providing an encrypted data block. Application can be made to secured integrated circuits requiring to securely store data in an external memory.

Abstract: A method for protecting a generation, by an electronic circuit, of at least one prime number by testing the prime character of successive candidate numbers, including: for each candidate number: the calculation of a reference number involving at least one first random number, and at least one primality test based on modular exponentiation calculations; and for a candidate number having successfully passed the primality test: a test of consistency between the candidate number and its reference number.

Abstract: A method and an element for ciphering with an integrated processor data to be stored in a memory, including applying to each data block to be ciphered a ciphering algorithm which is a function of at least one key specific to the integrated circuit, and before applying the ciphering algorithm thereto, combining the data block to be ciphered with the result of a function of the storage address of the ciphered block in the memory, and/or of combining the key with the result of a function of the storage address of the ciphered block in the memory and of a digital quantity different from the ciphering key.

Abstract: A method for recording at least one block of variable data in a first volatile memory external to a microprocessor, including calculating and storing a digital signature taking into account at least partially the address and the content of said data block in the memory, and at least a first random digital value internal to the microprocessor.

Abstract: An offline payment method includes communicating a commitment value calculated by an electronic check medium to a terminal configured to receive a payment from the electronic check medium. The commitment value is calculated based on a first authentication code and secret key, wherein the first authentication code is calculated based on a payment amount and secret verification key. The terminal determines and communicates a random/pseudo-random guesstimation to the electronic check medium in response to receiving the verification code, the random/pseudo-random guesstimation being configured to verify that the electronic check medium is authentic. The electronic check medium determines and communicates a second authentication code to the terminal, the second authentication based upon the random/pseudo-random guesstimation.

Abstract: The invention concerns a method and a system for customizing electronic components (2), by substituting in a nonvolatile storage each one first secret key (Ks) with a second secret key (Ks?), using a secure authentication module (1) automatically generating said second key after reconstructing the first key from an identifier of the component during customization, which consists in conditioning, on the authentication module side, the supply of the second key for a current component upon reception of a confirmation message for key substitution of at least one previous component.

Abstract: A method and device for encrypting and/or decrypting binary data blocks protecting both confidentiality and integrity of data sent to or received from a memory. The encryption method comprises steps of: applying to the input data block a reversible scrambling process, the scrambling process providing a scrambled data block in which the bits of the input data block are mixed so that a modification of one bit in the scrambled data block impacts on every bit of the input data block, and applying to the scrambled data block a stream cipher encryption algorithm providing an encrypted data block. Application can be made to secured integrated circuits requiring to securely store data in an external memory.

Abstract: An offline payment method includes communicating a commitment value calculated by an electronic check medium to a terminal configured to receive a payment from the electronic check medium. The commitment value is calculated based on a first authentication code and a secret key, wherein the first authentication code is calculated based on a payment amount and a secret verification key. The terminal determines and communicates a random/pseudo-random guesstimation to the electronic check medium in response to receiving the verification code, the random/pseudo-random guesstimation being configured to verify that the electronic check medium is authentic. The electronic check medium determines and communicates a second authentication code to the terminal, the second authentication based upon the random/pseudo-random guesstimation.

Abstract: A method for recording at least one block of variable data in a first volatile memory external to a microprocessor, including calculating and storing a digital signature taking into account at least partially the address and the content of said data block in the memory, and at least a first random digital value internal to the microprocessor.