Abstract: The method, the mobile device, and the payment terminal of the invention relate to security of contactless payment performed during a purchase of products or services by using a short-range wireless communication between the mobile device and the payment terminal. Various external parameters associated to the payment transaction may be exchanged between the mobile device and the payment terminal. Preferred embodiments comprise external parameters such as respective positions of the mobile device and the payment terminal, time stamps related to transaction processing time or identifiers of each the mobile device and the payment terminal. Difference values related to these external parameters are verified by both the mobile device and the payment terminal by carrying out comparison with reference values before validation of the payment transaction by the payment terminal.

Abstract: The generation of hash values become popular with the storage of pin code by an authentication server, since the authentication server knows only the result of the hash function and not the pin code itself. Each time an authentication is requested, a hash function is executed on the received pin code and then compared with the stored reference hash value of the initial pin code. In order to improve the security of the hash value, it is proposed a method to produce a secure hash value (R) from a plaintext (P), said method comprising: —producing a first result (H) using an hash function of the plaintext (P), —obtaining an initial floating value (U0) by converting the first result (H) into a floating number representation of the first value (H), —updating a floating value (Un) by executing at least once a Transcendental function (TF) on the initial floating value (Un?1), —obtaining the secure hash value (R) by mixing the first result (H) with the updated floating value (Un).

Abstract: The generation of hash values become popular with the storage of pin code by an authentication server, since the authentication server knows only the result of the hash function and not the pin code itself. Each time an authentication is requested, a hash function is executed on the received pin code and then compared with the stored reference hash value of the initial pin code. In order to improve the security of the hash value, it is proposed a method to produce a secure hash value (R) from a plaintext (P), said method comprising: —producing a first result (H) using an hash function of the plaintext (P), —obtaining an initial floating value (U0) by converting the first result (H) into a floating number representation of the first value (H), —updating a floating value (Un) by executing at least once a Transcendental function (TF) on the initial floating value (Un?1), —obtaining the secure hash value (R) by mixing the first result (H) with the updated floating value (Un).

Abstract: The method, the mobile device, and the payment terminal of the invention relate to security of contactless payment performed during a purchase of products or services by using a short-range wireless communication between the mobile device and the payment terminal. Various external parameters associated to the payment transaction may be exchanged between the mobile device and the payment terminal. Preferred embodiments comprise external parameters such as respective positions of the mobile device and the payment terminal, time stamps related to transaction processing time or identifiers of each the mobile device and the payment terminal. Difference values related to these external parameters are verified by both the mobile device and the payment terminal by carrying out comparison with reference values before validation of the payment transaction by the payment terminal.

Abstract: At least one embodiment refers to a method for securely exchanging messages between at least two devices, each of them storing a shared secret key. The method comprises: at each device: generating a random number, then sending it to the other devices; determining a first key by a first operation based onto said secret key and each random number; determining a second key based on said first key and said random numbers; at a sending device: determining a pseudo message on the basis of the message and said random numbers; calculating then sending a cryptogram on the basis of said pseudo message and said second key; and at the receiving device: decrypting said cryptogram by means of said second key; and retrieving said message from said pseudo message.

Abstract: At least one embodiment refers to a method for securely exchanging messages between at least two devices, each of them storing a shared secret key. The method comprises: at each device: generating a random number, then sending it to the other devices; determining a first key by a first operation based onto said secret key and each random number; determining a second key based on said first key and said random numbers; at a sending device: determining a pseudo message on the basis of the message and said random numbers; calculating then sending a cryptogram on the basis of said pseudo message and said second key; and at the receiving device: decrypting said cryptogram by means of said second key; and retrieving said message from said pseudo message.

Abstract: A method of coding a secret, a numerical value d, subdivided into a number N of secret elements [di]n1, a composition law () applied to the elements di giving the value d. The following are calculated: (A) a first image (TN) of the secret by iterative calculation and application of the law () between the first image Ti-1 of rank i?1 and of the product according to this law of the element (di) of next rank and of a random value (Ri) of a first set, (B) a first numerical value (S1) by application of the law () to the N random values (Ri), (C) a second numerical value (S2) by application of the law to the N?1 random values (Aj) of a second set, (D) a second image T? of the secret by application of the inverse law () to the first image (TN) and to the second numerical value (S2) so as to generate an intermediate image (Tx) and then application of the inverse law to the intermediate image (Tx) and to the second numerical value (S2).

Abstract: A method of masking the end-of-life transition of a microprocessor electronic device including reprogrammable non-volatile memory containing an end-of-life state variable. On booting, the value of the variable is loaded into RAM. After executing any current command, it is verified whether the value of the variable stored in RAM is FALSE. If the response is negative, the end-of-life transition is executed. Otherwise, initialization or execution of the command is continued. On detecting an intrusive attack, it is instantiated by writing the TRUE value to the end-of-life state variable in RAM only and then deferring writing of the TRUE value to the variable in the non-volatile memory until the next write operation. The invention is applicable to any electronic device, smart card, etc.

Abstract: The invention concerns a method for executing cryptographic calculation in an electronic component, based on a specific cryptographic algorithm including at least one secret key operation (102) to be performed with a secret encryption key (103) comprising m secret encryption key blocks of n bits on a data block (101), wherein m and n are positive integers, and a non-linear operation (107).

Abstract: A method of protecting a program interpreted by a virtual machine comprises the inclusion of interference operations during the execution of each program instruction. The scrambling operations are selected according to a program digest, so as to vary when a single instruction belongs to two different programs. In this way, any attempt at reverse engineering from side channels is made possible.

Abstract: The method of verifying the integrity of an encryption key (K) obtained by combining at least two key portions (KM, M) in a protected zone (3) by using a commutative operator, comprises the steps of: using the commutative operator to perform a first combination between a key portion (KM) and a verification encryption key (Kv); using the commutative operator to perform in succession a combination between a key portion that has not yet been combined and a result obtained by an immediately preceding combination, until a last combination (Mv) is performed that includes all of the key portions; performing a combination in the protected zone (3) between the encryption key (K) to be verified and the last combination (Mv) of the verification encryption key (Kv) and the key portions (KM, M) in order to obtain a final verification key (Kf); encrypting verification data (Dv) by means of a symmetrical encryption algorithm (DES) using the final verification key (Kf); and making a comparison with a verification encryption

Abstract: A method of masking the end-of-life transition of a microprocessor electronic device including reprogrammable non-volatile memory containing an end-of-life state variable. On booting, the value of the variable is loaded into RAM. After executing any current command, it is verified whether the value of the variable stored in RAM is FALSE. If the response is negative, the end-of-life transition is executed. Otherwise, initialization or execution of the command is continued. On detecting an intrusive attack, it is instantiated by writing the TRUE value to the end-of-life state variable in RAM only and then deferring writing of the TRUE value to the variable in the non-volatile memory until the next write operation. The invention is applicable to any electronic device, smart card, etc.

Abstract: A method of coding a secret, a numerical value d, subdivided into a number N of secret elements [di]n1, a composition law () applied to the elements di giving the value d. The following are calculated: (A) a first image (TN) of the secret by iterative calculation and application of the law () between the first image Ti?1 of rank i?1 and of the product according to this law of the element (di) of next rank and of a random value (Ri) of a first set, (B) a first numerical value (S1) by application of the law () to the N random values (Ri), (C) a second numerical value (S2) by application of the law to the N?1 random values (Aj) of a second set, (D) a second image T? of the secret by application of the inverse law () to the first image (TN) and to the second numerical value (S2) so as to generate an intermediate image (Tx) and then application of the inverse law to the intermediate image (Tx) and to the second numerical value (S2).

Abstract: The method of verifying the integrity of an encryption key (K) obtained by combining at least two key portions (KM, M) in a protected zone (3) by using a commutative operator, comprises the steps of: using the commutative operator to perform a first combination between a key portion (KM) and a verification encryption key (Kv); using the commutative operator to perform in succession a combination between a key portion that has not yet been combined and a result obtained by an immediately preceding combination, until a last combination (Mv) is performed that includes all of the key portions; performing a combination in the protected zone (3) between the encryption key (K) to be verified and the last combination (Mv) of the verification encryption key (Kv) and the key portions (KM, M) in order to obtain a final verification key (Kf); encrypting verification data (Dv) by means of a symmetrical encryption algorithm (DES) using the final verification key (Kf); and making a comparison with a verification encryption

Abstract: A method of protecting a program interpreted by a virtual machine comprises the inclusion of interference operations during the execution of each program instruction. The scrambling operations are selected according to a program digest, so as to vary when a single instruction belongs to two different programs. In this way, any attempt at reverse engineering from side channels is made possible.

Abstract: The invention concerns a method for executing cryptographic calculation in an electronic component, based on a specific cryptographic algorithm including at least one secret key operation (102) to be performed with a secret encryption key (103) comprising m secret encryption key blocks of n bits on a data block (101), wherein m and n are positive integers, and a non-linear operation (107).