IDENTIFICATION OF CONTACTLESS CARDS

• US 20090127337A1
• Filed: 11/21/2007
• Published: 05/21/2009
• Est. Priority Date: 11/21/2007
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: KARGL, WALTER
• Granted Patent: US 8,905,312 B2
• Time in Patent Office: Days
• US Class Current: 235/449
• 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 communication system includes at least one contactless card configured to transmit an encoded identifier; and a reader configured to receive the encoded identifier and compare the received encoded identifier with an encoded reference card identifier, wherein the reader requests data from the contactless card if the encoded identifier matches the encoded reference card identifier.

Claims

1. A contactless card comprising:

a first memory configured to store a card identifier; and

an encoder configured to generate an encoded card identifier from the card identifier.

2. The contactless card of claim 1, wherein the encoder is a pseudo random number generator seeded by the card identifier.

3. The contactless card of claim 1, further comprising:

a second memory configured to store an application code; and

a mixer configured to combine the application code and the encoded card identifier.

4. The contactless card of claim 1, further comprising a transmitter configured to transmit a signal including the encoded card identifier.

5. The contactless card of claim 3, further comprising a transmitter configured to transmit a signal including the combined application code and encoded card identifier.

6. The contactless card of claim 3, wherein the mixer comprises an exclusive-or gate.

7. The contactless card of claim 3, wherein the first and second memories are portions of a single memory.

8. The contactless card of claim 4, wherein the transmitter is configured to delay sending the signal including the encoded card identifier for a random amount of time after receiving a signal including a polling query from a reader.

9. The contactless card of claim 5, wherein the transmitter is configured to delay sending the signal including the combined application code and encoded card identifier for a random amount of time after receiving a signal including a polling query from a reader.

10. A contactless card reader, comprising:

a receiver configured to receive a signal transmitted by a contactless card; and

a correlator configured to scan the signal to determine whether a card identifier matching a reference card identifier is encoded in the transmitted signal.

11. The contactless card reader of claim 10, wherein the receiver is further configured to receive signals transmitted respectively by a plurality of contactless cards, and the correlator is further configured to scan the plurality of received signals to determine whether card identifiers matching a plurality of reference card identifiers are encoded in the transmitted signals.

12. The contactless card reader of claim 10, further comprising an encoder configured to encode the reference card identifier to be provided to the correlator.

13. The contactless card reader of claim 12, wherein the encoder comprises a random number generator seeded with the reference card identifier.

14. The contactless card reader of claim 13, further comprising an identifier search device configured to provide the encoder with the reference card identifier.

15. The contactless card reader of claim 10, further comprising a mixer configured to combine the encoded card identifier with an application code.

16. A communication system comprising:

a contactless card configured to transmit a signal including an encoded card identifier; and

a reader configured to receive the signal including the encoded card identifier and to compare the received card identifier with an encoded reference card identifier.

17. The communication system of claim 16, wherein the contactless card comprises:

a first memory configured to store the card identifier;

an encoder configured to encode the card identifier to form the encoded card identifier; and

a transmitter configured to transmit a signal including the encoded card identifier.

18. The communication system of claim 17, wherein the contactless card further comprises:

a second memory configured to store an application code; and

a mixer configured to combine the encoded card identifier with the application code.

19. The communication system of claim 16, wherein the reader comprises:

a receiver configured to receive the signal including the encoded card identifier;

an identifier search device configured to provide the encoded reference card identifier; and

a correlator configured to compare the encoded card identifier with the encoded reference card identifier to determine whether the card identifier matches the reference card identifier.

20. The communication system of claim 16, wherein the reader requests data from the contactless card if the encoded card identifier matches the encoded reference card identifier.

21. A communication system comprising:

a plurality of contactless cards, each of which is configured transmit a signal including a respective encoded card identifier and an application code; and

a reader configured to receive the signals including the respective encoded card identifiers and application codes, to compare the received card identifiers and application codes with at least one encoded reference card identifier and reference application code, respectively, and to request data from any of the contactless cards if the respective encoded card identifier and/or application code matches the at least one encoded reference card identifier and/or reference application code, respectively.

22. A method of identifying a contactless card comprising:

receiving a signal including an encoded card identifier from a contactless card; and

correlating the encoded card identifier with an encoded reference card identifier to determine whether the encoded card identifier matches the encoded reference card identifier.

23. The method of claim 22, further comprising seeding a random number generator with the encoded reference card identifier to generate an encoded card identifier.

24. The method of claim 22, further comprising, if the encoded card identifier matches the encoded reference card identifier, storing the encoded card identifier in a memory.

25. The method of claim 22, further comprising combining the encoded identifier with an application code.