Abstract: The present invention relates to a method to generate prime numbers on board a portable device, said method comprising the steps of, each time at least one prime number is requested: when available, retrieve results from previously performed derivation calculation or, if not, select a start point for derivation; process derivation calculation to converge towards a prime number; if a prime number is found, store it and restart derivation calculation from a new start point; stop the derivation calculation after a predetermined amount of time; store intermediate results to be used a next time a prime number will be requested; output a stored prime number.

Abstract: The present invention relates to a method to generate prime numbers on board a portable device, said method comprising the steps of, each time at least one prime number is requested: when available, retrieve results from previously performed derivation calculation or, if not, select a start point for derivation; process derivation calculation to converge towards a prime number; if a prime number is found, store it and restart derivation calculation from a new start point; stop the derivation calculation after a predetermined amount of time; store intermediate results to be used a next time a prime number will be requested; output a stored prime number.

Abstract: Application protocol data units are conveyed in a universal serial bus so that a portable electronic object such as a smart card can be recognized by a terminal, such as a micro-computer, as being a peripheral. The header and the data field, when such a data field exists, of each command are encapsulated in data fields of data packets of respective downlink transactions. The data field, when such a data field exists, and the trailer of each response are encapsulated in the data packet data field of at least one uplink transaction. By means of this bus link, the data rate between the terminal and the electronic object is higher, and a plurality of portable electronic objects can be connected to the terminal.

Abstract: Application protocol data units are conveyed in a universal serial bus so that a portable electronic object such as a smart card can be recognized by a terminal, such as a micro-computer, as being a peripheral. The header and the data field, when such a data field exists, of each command are encapsulated in data fields of data packets of respective downlink transactions. The data field, when such a data field exists, and the trailer of each response are encapsulated in the data packet data field of at least one uplink transaction. By means of this bus link, the data rate between the terminal and the electronic object is higher, and a plurality of portable electronic objects can be connected to the terminal.

Abstract: Application protocol data units are conveyed in a universal serial bus so that a portable electronic object such as a smart card can be recognized by a terminal, such as a micro-computer, as being a peripheral. The header and the data field, when such a data field exists, of each command are encapsulated in data fields of data packets of respective downlink transactions. The data field, when such a data field exists, and the trailer of each response are encapsulated in the data packet data field of at least one uplink transaction. By means of this bus link, the data rate between the terminal and the electronic object is higher, and a plurality of portable electronic objects can be connected to the terminal.

Abstract: The invention provides a method for reducing occupancy of descriptors used for protecting files in storage. The method includes separating the functions files are going to be subjected to from the protection modes to which said functions subscribe. The descriptors comprise a number of octets equal to the number of protection modes proposed. The bits of these octets, depending on whether they are active or inactive, refer to function memory words whose number is directly equal to the number of active bits in the mode memory words. The function memory words comprise references to secret codes to be used for implementing the desired security functions.

Abstract: Application protocol data units are conveyed in a universal serial bus so that a portable electronic object such as a smart card can be recognized by a terminal, such as a micro-computer, as being a peripheral. The header and the data field, when such a data field exists, of each command are encapsulated in data fields of data packets of respective downlink transactions. The data field, when such a data field exists, and the trailer of each response are encapsulated in the data packet data field of at least one uplink transaction. By means of this bus link, the data rate between the terminal and the electronic object is higher, and a plurality of portable electronic objects can be connected to the terminal.

Abstract: Microprocessor-based cards use application programs contained in a non-volatile user memory (MU), under the control of an operating system in a read-only memory (MSYS). To provide flexibility and security of access to the various memory zones without using a specific rigidly fixed circuitry, it is proposed that the memory access instructions of the application programs (PG1, PG2, PG3) should be interpreted and not performed directly. The interpreter is in the read-only memory (MSYS) or in the user memory and it carries out an access instruction as follows: it explores a reserved zone (ZR) of the user memory to find out if the requested access (access for reading, writing or performance) is cleared for the requested address. It performs the instruction only if the clearance is present. The reserved zone (ZR) which contains these clearances is updated during the writing, in the user memory, of a new application program. The updating can be done only by the operating system.