Abstract:
The invention concerns an antenna generating an electromagnetic field for an electromagnetic transponder, and a terminal provided with such an antenna, comprising a first inductive element (Lp) designed to be connected to two terminals (3, 4) applying an energizing voltage (Vg), and a parallel resonant circuit (21) coupled with the first inductive element.
Abstract:
The invention relates to a method and a circuit for extracting a secret datum from an integrated circuit involved in an authentication procedure. The secret datum is obtained at least partially from a network of physical parameters that are linked to the production of the integrated circuit chip. Said secret datum is generated upon request and made ephemeral.
Abstract:
PROBLEM TO BE SOLVED: To provide a method and a device for storing and reading digital data on/from a physical medium. SOLUTION: The method and the device to secure storage of digital data on a physical medium equipped with a calculation means by a recorder include, upon first use of the medium in a write mode, a step of memorizing at least one identifier of a reader of the medium in the medium or its calculation means in a non-volatile manner and a step of storing the data in an encrypted manner by an encryption key to be permanently included in the medium or its calculation means. The method and the device are for reading such encrypted data. COPYRIGHT: (C)2003,JPO
Abstract:
PROBLEM TO BE SOLVED: To provide a terminal that generates an electromagnetic field for communication with at least one transponder, and to provide a method for controlling this terminal. SOLUTION: The terminal is provided with an oscillation circuit, that is excited by a remote supply signal from the transponder, an amplitude demodulator that detects data sent from the transponder, a means for regulating a signal phase of the oscillation circuit of the terminal to be a reference value, a means for measuring a variable linked with a current and a voltage of the oscillation circuit, and a means for comparing the present value of the variable with a prescribed value to decide as to whether the transponder is present.
Abstract:
PROBLEM TO BE SOLVED: To reduce heating of a transponder when an operation power to a proximate transponder from a terminal is supplied by a radio by providing a means for detuning an oscillation circuit from a specific transmission frequency when the transponder approaches the terminal. SOLUTION: A terminal 1' is between an output terminal 2p of an amplifier, that is, an antenna coupler 3, and a terminal 2m in a reference potential (generally a ground), and includes an oscillation circuit consisting of a capacity parts 24, a resistor R1 and a serial impedance, that is, an antenna L1. Then, when the oscillation circuit of the terminal 1' and/or the oscillation circuit of a transponder are in a very close coupling relationship, in order to detune these, a phase of a current of the antenna L1 is adjusted to a reference signal REF. This adjustment is executed by changing a capacitance C1 of the oscillation circuit of the terminal 1' and maintaining the antenna current to a constant phase relationship with the reference signal.
Abstract:
PROBLEM TO BE SOLVED: To provide a method and a device for secured identification by using biometric data and an integrated circuit chip when using an arbitrary function with biometric data. SOLUTION: The digital biometric data obtained by a sensor 1 is combined with identification data (CHIPID) of the integrated circuit chip contained in a device common to the sensor 1. The chip identification data (CHIPID) is obtained from a physical parameter network 17 and is formed to perform secured authentication. COPYRIGHT: (C)2003,JPO
Abstract:
PROBLEM TO BE SOLVED: To provide a method for generating secret quantities by an integrated circuit according to the destination of these secret quantities. SOLUTION: In a method and a circuit for generating several secret quantities by the integrated circuit according to the destination of these secret quantities, a first digital ward forming a single identifier of the integrated circuit chip and coming from a physical parameter network is taken into account and this identifier is individualized according to an application. COPYRIGHT: (C)2003,JPO
Abstract:
PROBLEM TO BE SOLVED: To measure distance to a terminal on a transponder side by comparing DC voltage level information when an oscillation circuit being arranged on the upstream side from the DC voltage rectification means of a transponder is tuned or detuned from a fixed frequency. SOLUTION: The transponder 30 is provided with an inductance L2 and a capacitor C2 between terminals 11 and 12 as an oscillation circuit. The voltage of a capacitor Ca is subjected to single half-wave rectification by a diode D. A reference voltage 15 corresponds to the negative terminal of the capacitor Ca that is connected to the terminal 12. A DC supply voltage Va is inputted to input DET being connected to the microprocessor of an electronic block 31. A capacitor C3 is connected in series with a switch K1 and is located between the terminals 11 and 12. When the transponder 30 is in a terminal region, power is supplied, the transistor K1 is turned on, and an oscillation circuit is turned for recharging the terminal DET. After that, the transistor K1 is turned off, and the circuit is detuned and the terminal DET is recharged again. The two DC voltage values are compared and are stored at a single bit.
Abstract:
PROBLEM TO BE SOLVED: To avoid a transmission gap (distance where a terminal can detect a transponder) and also to maintain a maximum system range by providing two capacitive modulating means and connecting the reference terminal of each modulating means to the reference supply potential of an electronic circuit on the secondary side of a rectifying means. SOLUTION: This transponder 10' is formed from an oscillation circuit consisting of an inductance L2 and a capacitor C2 parallelly connected between two alternating current input terminals 11 and 12 of a rectifier bridge 13 consisting of rectifier diodes D1 to D4. The rectifier output terminals 14 and 15 of the bridge 13 supply a service voltage to an electronic circuit 17 such as a processor P through a filtering capacitor Ca. Two capacitive modulating means (consisting of C3, K1, C4 and K2) respectively connected to the terminals 11 and 12 of both ends of a dielectric element L2 of an oscillation circuit are included, and the reference terminal of each modulating means is connected to a reference supply potential 15 of the circuit 17 on the secondary side of a rectifying means 13.
Abstract:
PROBLEM TO BE SOLVED: To permit operation only in an extreme proximity to prevent the surreptitious use due to interception by allowing a resonance circuit to have a specific characteristic that an electromagnetic coupling coefficient is suddenly reduced when the distance exceeds a prescribed value between a write/read terminal and an electromagnetic transponder. SOLUTION: The voltage that is induced by a transponder 10 is maximized with an optimum coupling coefficient set between a serial resonance circuit including a resistor R1, an inductance L1 and a capacitor C1 of a terminal 1 and a parallel oscillation circuit including an inductance L2 and a capacitor C2 of the transponder 10 and then reduced sharply on both sides of the transponder 10. Then the optimum coupling coefficient is expressed by a square root of R1L2/R2L1 with equivalent resistor R2 of the transponder 10, and each parts value of every oscillation circuit is set to secure the maximum voltage with a prescribed distance. In other words, the capacitor C2 that can obtain a prescribed frequency with a distance of 1 cm is reduced as much as possible and then the value of inductances L2 and L1 and capacitor C1 are successively set.