Abstract: A method for monitoring the execution of a sequence of instruction codes in an integrated circuit comprising a central processing unit provided for executing such instruction codes. In one embodiment, the method comprises producing current cumulative signatures during the execution of a sequence, until a final cumulative signature is obtained, producing an error signal having a value active by default while the current cumulative signature is different to an expected signature, measuring a predetermined time interval that is substantially longer than the presumed duration of execution of the sequence, masking the error signal during the measurement of the time interval, and lifting the masking of the error signal when the time interval expires.

Abstract: An electronic circuit comprises a plurality of configurable cells configured according to a chaining command signal. These configurable cells are configured either in a chained state in which the configurable cells are functionally connected in a chain to form a shift register, if the chaining command signal is in a first state, or in a functional state in which the configurable cells are functionally linked to logic cells with which they co-operate to form at least one logic circuit, if the mode command signal is in a second state. It is provided that a test data word will be preceded by a signature. The set formed by the digital signature and the data word forms a test sequence. The signature is verified before the introduction of the test data word by an appropriate detection circuit.

Abstract: An electronic circuit includes a plurality of configurable cells configured by a control circuit such as a test access controller when it receives a mode command signal: either in a functional state in which the configurable cells are functionally linked to logic cells with which they co-operate to form at least one logic circuit if the mode command signal is in a first state or in a chained state in which the configurable cells are functionally connected in a chain to form a shift register, if the mode command signal is in a second state. The electronic circuit also includes a detection circuit laid out to produce an active state signal if it detects a chained state of the configurable cells while the controller receives the mode command signal in the first state.

Abstract: An electronic circuit, including: a logic circuit having a plurality of logic cells; storage cells able to form a shift register, able to be connected to the logic cells; a connection control module having an input for the reception of an identification key, the module connecting the storage cells so as to form a test shift register when the receive input receives a valid identification key, and the module connecting the storage cells so as to form randomly a diversion circuit when the input does not receive a valid identification key. The invention allows the electronic circuit to be protected against fraudulent access in read or write mode. The invention also relates to a smart card including this electronic circuit.

Abstract: An electronic circuit, including; a logic circuit having a plurality of logic cells; storage cells able to form a shift register, able to be connected to the logic cells; a connecting control module having an input for the reception of an identification key, the module connecting the storage cells so as to form a test shift register when the receive input receives a valid identification key, and the module connecting the storage cells so as to form randomly a diversion circuit when the input does not receive a valid identification key. The invention allows the electronic circuit to be protected against fraudulent access in read or write mode. The invention also relates to a smart card including this electronic circuit.

Abstract: An electronic circuit includes a logic circuit formed from a plurality of logic units. The electronic circuit also includes a plurality of memory units capable of forming a shift register, capable of being connected to the logic units, and having terminals for reception of command signals to write data into the logic units and to read data from the logic units. The electronic circuit further includes an access controller having a plurality of outputs connected to the terminals of the memory units and capable of applying the command signals to the outputs. In addition, the electronic circuit includes a scrutinizing module capable of a plurality of functions.

Abstract: An electronic circuit, including: a logic circuit having a plurality of logic cells; storage cells able to form a shift register, able to be connected to the logic cells; a connection control module having an input for the reception of an identification key, the module connecting the storage cells so as to form a test shift register when the receive input receives a valid identification key, and the module connecting the storage cells so as to form randomly a diversion circuit when the input does not receive a valid identification key. The invention allows the electronic circuit to be protected against fraudulent access in read or write mode. The invention also relates to a smart card including this electronic circuit.

Abstract: An electronic circuit containing a processing unit for executing program instructions, including at least one unit for recognizing at least one first instruction operator in the program and for converting this first operator into another instruction operator, both operators being interpretable by the processing unit. A method for controlling the access to data by such a circuit.

Abstract: A method and device detect synchronization errors between logic signals of a group of logic signals. A control word is loaded into a shift register arranged in loop and clocked by resulting logic signals equal to the result of the OR logic function and to the result of the AND logic function applied to the logic signals of the group of logic signals. The value of the control word is monitored as it propagates in the shift register, and a synchronization error signal is sent if the control word changes value. Application in particular for checking the integrity of a clock tree in an integrated circuit.

Abstract: A method reads a datum saved in a memory by selecting an address of the memory in which the datum to be read is saved, reading the datum in the memory at the selected address, saving the datum read in a storage space, and when the memory is not being accessed by a CPU, reading the datum in the memory, reading the datum saved in the storage space, and activating an error signal if the datum read in the memory is different from the datum saved. The method can be applied particularly to the protection of smart card integrated circuits.

Abstract: A device and a method detect an acceleration of a logic signal expressed by a closure, beyond a closure threshold, of at least two variation edges of the logic signal. A first control bit and a second control bit are provided. At each edge of the logic signal, the value of the first control bit is inverted after a first delay and the value of the second control bit is inverted after a second delay. An acceleration is detected when the two control bits have at the same time their respective initial values or their respective inverted initial values. Application is in particular but not exclusively to the detection of error injections in a secured integrated circuit.

Abstract: An electronic circuit includes a plurality of configurable cells configured by a control circuit such as a test access controller when it receives a mode command signal: either in a functional state in which the configurable cells are functionally linked to logic cells with which they co-operate to form at least one logic circuit if the mode command signal is in a first state or in a chained state in which the configurable cells are functionally connected in a chain to form a shift register, if the mode command signal is in a second state. The electronic circuit also includes a detection circuit laid out to produce an active state signal if it detects a chained state of the configurable cells while the controller receives the mode command signal in the first state.

Abstract: An electronic circuit includes configurable cells each having a test input and an output. The configurable cells are connected to one another in a chain in a predefined order via their test input and their output to form a test register based on receiving a chaining command signal. The electronic circuit also includes a detection circuit activated by the chaining command signal to produce a state signal representing a state of initialization of a first set of configurable cells A multiplexing circuit selectively connects the test input of each configurable cell to a second set of the configurable cells either to the output of a preceding configurable cell or to an output of a decoy data generator based on the state signal.

Abstract: An electronic circuit, having a test mode in application of the “internal scan path” technique, includes a plurality of configurable cells and a control circuit. The electronic circuit is adapted to working in a standard mode of operation or in a test mode during which the control circuit is active and configures the configurable cells either in a functional state or in a chained state. The electronic circuit furthermore includes a validation circuit that performs the following operations successively when it receives an instruction for changing the mode of operation (TEST, FIN) of the electronic circuit: produce initialization signals (INIT1, INIT2, . . . , INITN) to command the initialization of all the configurable cells, and then produce a mode-changing signal (VAL).

Abstract: An electronic circuit includes configurable cells capable of being functionally linked to logic cells with which they cooperate to form at least one logic circuit if a chaining command signal is in a first (inactive) state. The electronic circuit also includes a logic interconnection circuit for performing the following functions if the chaining command signal is in a second (active) state. Functionally connecting the configurable cells in a linear feedback shift register if an authentication signal is in a first state, or functionally connecting the configurable cells in a chain in a predefined order to form a shift register if the authentication signal is in a second state.

Abstract: An electronic circuit includes configurable cells with a test input and an output. The configurable cells are capable of being connected to one another in a chain in a predefined order via the test inputs and the outputs to form a test shift register if they receive a chaining command signal. A connection control module disconnects the test input from at least one configurable cell if the connection control module receives an invalid identification key. The connection control module leaves disconnected the test input from the at least one configurable cell, or applies a constant potential on the test input of the at least one configurable cell, or connects the test input of the at least one configurable cell at an output of a random-data generator.

Abstract: An electronic circuit comprises a plurality of configurable cells configured according to a chaining command signal. These configurable cells are configured either in a chained state in which the configurable cells are functionally connected in a chain to form a shift register, if the chaining command signal is in a first state, or in a functional state in which the configurable cells are functionally linked to logic cells with which they co-operate to form at least one logic circuit, if the mode command signal is in a second state. It is provided that a test data word will be preceded by a signature. The set formed by the digital signature and the data word forms a test sequence. The signature is verified before the introduction of the test data word by an appropriate detection circuit.

Abstract: An electronic circuit comprises configurable cells driven by command signals to adopt either a standard mode of operation in which they are integrated into a logic circuit, or a test mode in which they provide information on this logic circuit. The circuit includes a spy circuit capable of detecting an abnormal excitation of certain of the conductors through which the command signals travel, thus preventing fraudulent extraction of data out of the configurable cells. The spy circuit includes a logic combination circuit and a state detection cell.

Abstract: A method secures a memory in which individually read-accessible binary words are saved. The method includes defining a memory zone covering a plurality of words, calculating a cumulative signature according to all of the words in the memory zone, and storing the cumulative signature as an expected signature of the memory zone to check the integrity of data read in the memory. The method can be applied to the securing of smart cards.

Abstract: The present invention relates to a coprocessor comprising a calculation unit for executing a command, and a securisation device for monitoring the execution of the command and supplying an error signal having an active value as soon as the execution of the command begins and an inactive value at the end of the execution of the command, if no abnormal progress in the execution of the command has been detected. The coprocessor further comprises means for preventing access to at least one unit of the coprocessor, while the error signal is on the active value. Application is provided particularly but not exclusively to the protection of integrated circuits for smart cards against attacks by fault injection.