AUTHENTICATION OF AN ELECTROMAGNETIC TERMINAL-TRANSPONDER COUPLE BY THE TRANSPONDER

• US 20100328026A1
• Filed: 06/15/2010
• Published: 12/30/2010
• Est. Priority Date: 06/25/2009
• Status: Active Grant

• Current Assignee: STMicroelectronics SAS (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SAS (STMicroelectronics NV)
• Inventors: Wuidart, Luc
• Granted Patent: US 8,446,259 B2
• Time in Patent Office: Days
• US Class Current: 340/5.8
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07336 Active means, e.g. jamming or scrambling of the electromagnetic field

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 the transponder: receives 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; and exploits these first data and second data relative to the level of said D.C. voltage, respectively measured for the first resistive load value and for a second resistive load value.

Claims

1. A method of authentication of a terminal generating a magnetic field, by a transponder comprising an oscillating circuit from which a D.C. voltage is generated, wherein the transponder:

receives 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; and

exploits these first data and second data relative to the level of said D.C. voltage, respectively measured for said first resistive load value and for a second resistive load value.

2. The method of claim 1, wherein the transponder:

evaluates, based on said data, a ratio between values of the current in the oscillating circuit of the terminal; and

compares this ratio with said first data.

3. The method of claim 1, wherein the transponder:

evaluates, based on said data, a value of said voltage; and

compares this evaluated value with the measured value.

4. The method of claim 1, wherein the first data correspond to the ratio of the current in the oscillating circuit of the terminal while no transponder is present in its field to a value of this current with the first resistive load value of the transponder.

5. The method of claim 1, wherein in the absence of an authentication, the transponder sends intentionally incorrect data.

6. A method for authenticating a terminal generating a magnetic field and a transponder which is present in this field, wherein:

the terminal is authenticated by the transponder according to claim 1; and

to authenticate the transponder, the terminal;

receives third data relative to the current in the oscillating circuit of the terminal, evaluated for a second value of the resistive load of the transponder; and

compares the third data with fourth corresponding data obtained by measurement.

7. The method of claim 6, wherein the third and fourth data are ratios of the current in the oscillating circuit of the terminal while no transponder is present in its field and of this same current with the second value of the resistive load.

8. The method of claim 6, wherein, in the absence of an authentication by the terminal, said terminal sends intentionally incorrect data.

9. An electromagnetic transponder comprising:

an oscillating circuit upstream of a rectifying circuit capable of providing a D.C. voltage when the transponder is present in the magnetic field of a terminal; and

at least one processing unit capable of implementing the method of claim 1.

10. A terminal capable of generating an electromagnetic field for a transponder, comprising means capable of implementing the method of claim 1.