AUTHENTICATION OF AN ELECTROMAGNETIC TERMINAL-TRANSPONDER COUPLE BY THE TERMINAL

• US 20100328027A1
• 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 8,907,761 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
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

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.

Claims

1. 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.

2. The method of claim 1, wherein the transponder evaluates said second data based on said first data and on fourth data relative to the level of a D.C. voltage generated by an oscillating circuit of the transponder, respectively measured for said first value of the resistive load and for a second resistive load value.

3. The method of claim 1, wherein said data are ratios of the current in the oscillating circuit of the terminal while no transponder is located in its field and of this same current with the values of the resistive load.

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

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

the transponder is authenticated by the terminal of claim 1; and

to authenticate the terminal, the transponder exploits said first and fourth data.

6. The method of claim 5, wherein the transponder:

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

compares this ratio with said first data.

7. The method of claim 5, wherein the transponder:

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

compares this evaluated value with the measured value.

8. The method of claim 6, wherein, in the absence of an authentication by the transponder, said transponder 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 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.