Abstract: A method for managing the power in an electromagnetic transponder in the field of a terminal, including the steps of: evaluating the power consumption of the transponder circuits; and if this power consumption is below a threshold, evaluating the current coupling factor between the transponder and the terminal and, according to the current coupling: causing an increase of the transponder power consumption or causing a detuning of an oscillating circuit of the transponder.

Abstract: A method for protecting communication between an electromagnetic transponder and a terminal, wherein the transmission of a polling request by the terminal is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with the terminal.

Abstract: A method for assisting with positioning of an electromagnetic transponder by a user with respect to a terminal, wherein: a current value of a ratio of the current coupling factor between the transponder and the terminal to an optimum coupling factor with a first resistive load value is calculated and stored; the current value is compared with a previous value of this ratio, stored in a previous iteration; and data elements intended for the user are controlled according to the comparison.

Abstract: A method for assisting with positioning of an electromagnetic transponder by a user with respect to a terminal, wherein: a first value of the current in an oscillating circuit of the terminal is periodically measured; a second value of a ratio between a no-load value of this current, stored when no transponder is in the field of the terminal, and the first value, is calculated; and pieces of information intended for the user are controlled according to said second value.

Abstract: A method for protecting communication between an electromagnetic transponder and a terminal, wherein the transmission of an acknowledgement for a request received from a terminal by the transponder is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with the terminal.

Abstract: A method for setting the clock frequency of a processing unit of an electromagnetic transponder, wherein a ratio between data, representative of a voltage across an oscillating circuit of the transponder and obtained for two values of the resistive load, is compared with one to decide whether to increase or decrease the clock frequency of the processing unit.

Abstract: A method of power recovery by an electromagnetic transponder in the field of a terminal, wherein: a ratio of the current coupling factor of the transponder with the terminal to an optimum coupling position with a resistive load value is evaluated; and a detuning of the oscillating circuit is caused if the ratio is greater than a first threshold greater than or equal to one.

Abstract: A method of authentication of a terminal generating a magnetic field by a transponder including an oscillating circuit from which a D.C. voltage is generated, wherein at least one quantity depending on the coupling between the transponder and the terminal is compared with at least one reference value.

Abstract: A method of evaluation, by an electromagnetic transponder in the field of a terminal generating a magnetic field, of power that can be extracted from this field, including the steps of: evaluating the current coupling between the transponder and the terminal; and deducing therefrom information relative to the power available in this coupling position.

Abstract: A method of authentication, by a terminal generating a magnetic field, of a transponder located in this field, wherein: first data, relative to the current in an oscillating circuit of the terminal, measured by the terminal for a first value of the resistive load of the transponder, are transmitted to the transponder; second corresponding data are evaluated by the transponder for a second value of the resistive load and are transmitted to the terminal; and said second data are compared with third corresponding data, measured by the terminal for the second value of the resistive load.

Abstract: A process is provided for fabricating a wafer including a plurality of chips separated by scribe lines. The method includes locking at least one chip on the wafer using a secret key, and writing the secret key into at least one memory present on the wafer.

Abstract: A method for evaluating the current coupling factor between an electromagnetic transponder and a terminal, and a transponder implementing this method, wherein a ratio between data representative of a voltage across an oscillating circuit of the transponder and obtained for two capacitance values of the oscillating circuit is compared with one or several thresholds.

Abstract: A method for protecting an integrated circuit. According to the method, the start-up of all, or part, of the circuit is determined in the presence of a key which is recorded in a non-volatile manner in the circuit, following the production thereof, and depends on at least one first parameter which is present in a non-volatile manner in the circuit after the production thereof.

Abstract: A transponder comprising a resonant circuit, comprising an antenna and a capacitor, and at least one memory connected to the resonant circuit via an intermediate circuit, characterized in that the intermediate circuit comprises at least one contact zone for receiving a portion of human body, so that the positioning of a portion of human body on a contact zone modifies the intermediate circuit, capable of switching from a first state in which it does not allow the memory to be read and/or written to a second state in which it allows the memory to be read and/or written when the resonant circuit of the transponder is contactlessly powered by a reader.

Abstract: A method for protecting communication between an electromagnetic transponder and a terminal, wherein the transmission of a polling request by the terminal is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with the terminal.

Abstract: A method for protecting communication between an electromagnetic transponder and a terminal, wherein the transmission of an acknowledgement for a request received from a terminal by the transponder is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with the terminal.

Abstract: A method for assisting with positioning of an electromagnetic transponder by a user with respect to a terminal, wherein: a current value of a ratio of the current coupling factor between the transponder and the terminal to an optimum coupling factor with a first resistive load value is calculated and stored; the current value is compared with a previous value of this ratio, stored in a previous iteration; and data elements intended for the user are controlled according to the comparison.

Abstract: A method for assisting with positioning of an electromagnetic transponder by a user with respect to a terminal, wherein: a first value of the current in an oscillating circuit of the terminal is periodically measured; a second value of a ratio between a no-load value of this current, stored when no transponder is in the field of the terminal, and the first value, is calculated; and pieces of information intended for the user are controlled according to said second value.

Abstract: A method for evaluating the current coupling factor between an electromagnetic transponder and a terminal, wherein a ratio between data, representative of a voltage across an oscillating circuit of the transponder and obtained for two values of the resistive load, is compared with one or several thresholds.

Abstract: Transponder comprising a resonant circuit, comprising an antenna and a capacitor, and at least one memory, wherein it comprises at least one contact zone for receiving a portion of human body, so that the positioning of a portion of human body on a contact zone modifies the electric circuit of the transponder, capable of switching from a first state in which it does not allow the memory to be read and/or written to a second state in which it allows the memory to be read and/or written when the resonant circuit of the transponder is contactlessly powered by a reader and in that it comprises an indicator which makes it possible to indicate that the positioning of a portion of human body on the contact zone of the transponder is or has been recognized.