Abstract: Generation of a message m of order ?(n) for a test of the integrity of the generation of a pair of cryptographic keys within the multiplicative group of integers modulo n=p·q, including: —key pair generation including, to generate p and q: a random selection of candidate integers; and a primality test; —a first search of the multiplicative group of integers modulo p for a generator a; —a second search of the multiplicative group of integers modulo q for a generator b; —a third search for a number y, as message m, verifying: 1???n?1, where ?=a mod p and ?=b mod q, the first or second search being performed during the primality test.

Abstract: Method of integrity verification of cryptographic key pairs, the method including an integrity test with: at least one first step implementing one of the private and public keys and an initial test datum, the first step making it possible to generate a first result, at least one second step implementing at least the first result and the key not used during the at least one first step, the second step making it possible to generate a second result, and a comparison of the second result and of the initial test datum, characterized in that the test is re-executed upon each positive comparison, and in that the test is executed at least 2 times.

Abstract: Method of integrity verification of public and private cryptographic key pairs in the additive group of integers modulo n, with n being the product of two prime numbers p and q, the method including the following steps: of computation (201), on the basis of the number n, of a public exponent e of the public key, and of a private exponent d of the private key, of two candidate factors p? and q? corresponding respectively to the numbers p and q, of verification (206) so as to verify the consistency of the private exponent with respect to the public exponent and to the number n, the verification step involving the candidate factors.

Abstract: Generation of a message m of order ?(n) for a test of the integrity of the generation of a pair of cryptographic keys within the multiplicative group of integers modulo n=p·q, including: —key pair generation including, to generate p and q: a random selection of candidate integers; and a primality test; —a first search of the multiplicative group of integers modulo p for a generator a; —a second search of the multiplicative group of integers modulo q for a generator b; —a third search for a number y, as message m, verifying: 1???n?1, where ?=a mod p and ?=b mod q, the first or second search being performed during the primality test.

Abstract: A method of cryptographic processing of data (X), in particular a method protected against fault injection attacks, and an associated device. The processing includes at least one transformation (100, 1001-1006) of an input data item (s) into a result data item (s?). In this case the method includes a step (E204) of verifying the transformation including the following steps: obtaining (E206) a first data item (DV(s?)) that is compressed by applying a compression operation (110, MDV, ADV) to the result data item (s?); obtaining (E208) a second compressed data item (DV(s)) that is compressed by applying the compression operation (110, MDV, ADV) to the input data item (s); determining (E210) a verification data item (DV(s)?) by applying the transformation (100, 1001-1006) to the second compressed data item (DV(s)) and; comparing (E212) the verification data item and the first compressed data item.

Abstract: Method of integrity verification of cryptographic key pairs, the method including an integrity test with: at least one first step implementing one of the private and public keys and an initial test datum, the first step making it possible to generate a first result, at least one second step implementing at least the first result and the key not used during the at least one first step, the second step making it possible to generate a second result, and a comparison of the second result and of the initial test datum, characterized in that the test is re-executed upon each positive comparison, and in that the test is executed at least 2 times.

Abstract: Method of integrity verification of public and private cryptographic key pairs in the additive group of integers modulo n, with n being the product of two prime numbers p and q, the method including the following steps: of computation (201), on the basis of the number n, of a public exponent e of the public key, and of a private exponent d of the private key, of two candidate factors p? and q? corresponding respectively to the numbers p and q, of verification (206) so as to verify the consistency of the private exponent with respect to the public exponent and to the number n, the verification step involving the candidate factors.

Abstract: A method of cryptographic processing of data (X), in particular a method protected against fault injection attacks, and an associated device. The processing includes at least one transformation (100, 1001-1006) of an input data item (s) into a result data item (s?). In this case the method includes a step (E204) of verifying the transformation including the following steps: obtaining (E206) a first data item (DV(s?)) that is compressed by applying a compression operation (110, MDV, ADV) to the result data item (s?); obtaining (E208) a second compressed data item (DV(s)) that is compressed by applying the compression operation (110, MDV, ADV) to the input data item (s); determining (E210) a verification data item (DV(s)?) by applying the transformation (100, 1001-1006) to the second compressed data item (DV(s)) and; comparing (E212) the verification data item and the first compressed data item.