Transponder, RFID system, and method for RFID system with key management

• US 20080012690A1
• Filed: 07/05/2007
• Published: 01/17/2008
• Est. Priority Date: 07/05/2006
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Friedrich, Ulrich
• Granted Patent: US 8,296,852 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/3066 involving algebraic varieties, e.g. elliptic or hyper-elliptic curves

Abstract

A transponder is provided, in particular a passive and/or backscatter-based transponder, for an RFID system, wherein at least one first piece of information can be stored in a first memory area on the transponder that is accessible in clear text only by a read access internal to the transponder, and a second piece of information can be stored in a second memory area that is accessible in clear text through an air interface for read access, and the second piece of information is generated from the first piece of information using an asymmetric encryption method. The invention further relates to an RFID system for wireless data exchange comprising a transponder and a base station, and a method for requesting write and/or read access to a transponder, in particular a passive and/or backscatter-based transponder.

Claims

1. A transponder for an RFID system, in particular a passive and/or backscatter-based transponder, comprising:

a first memory area provided in the transponder for storing at least one first piece of information that is accessible in clear text only by a read access internal to the transponder; and

a second memory area for storing a second piece of information that is accessible in clear text through an air interface for read access,

wherein the second piece of information is generated from the first piece of information using a public key of an asymmetric encryption method.

2. The transponder according to claim 1, wherein the first piece of information is a symmetric password that is accessible internally to the transponder by an internal logic unit of the transponder for a password comparison.

3. The transponder according to claim 1, wherein a third piece of information is stored on the transponder which identifies a coding for generating the second piece of information.

4. The transponder according to claim 3, wherein a security measure protects the second and/or third piece of information from read access through the air interface.

5. The transponder according to claim 1, wherein the asymmetric encryption method is an elliptic curve cryptosystem method.

6. An RFID system for a wireless data exchange comprising at least one transponder according to claim 1 and at least one base station, wherein the first piece of information is calculated by the base station from the second piece of information and a key corresponding to the asymmetric encryption method of the transponder, and wherein write and/or read access for the base station to at least one first data area of the transponder is enabled after the first piece of information has been received.

7. The RFID system according to claim 6, wherein the transponder has at least one second data area, and wherein the write and/or read access to the second data area of the transponder is enabled without transmission of the first piece of information.

8. A method for requesting write and/or read access to a transponder for an RFID system according to claim 1, the method comprising:

protecting the write and/or read access to the transponder by the first piece of information;

reading the second piece of information from the transponder by a base station;

calculating the first piece of information by the base station from the second piece of information and a key corresponding to the asymmetric encryption method; and

requesting a write and/or read access to the transponder by the base station with transmission of the first piece of information.

9. The method according to claim 8, wherein the base station determines the key, at least a portion thereof, from a base station memory area.

10. The method according to claim 8, wherein an elliptic curve cryptosystem method is used as the asymmetric encryption method.

11. The method according to claim 8, wherein the key is determined by the base station using a third piece of information.

12. The method according to claim 11, wherein the third piece of information is read from the transponder.

13. The method according to claim 11, wherein the third piece of information is determined from an agreement.

14. The method according to claim 8, wherein the first piece of information is transmitted to the transponder as defined in a protocol.