Secure two-way RFID communications

• US 20070177738A1
• Filed: 02/17/2006
• Published: 08/02/2007
• Est. Priority Date: 09/11/2003
• Status: Abandoned Application

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Esterberg, Aanand, Diorio, Christopher, Humes, Todd
• Application Number:
  US11/356,885
• Publication Number:
  US 20070177738A1
• Time in Patent Office: Days
• US Class Current: 380/270
• 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
• CPC Class Codes: G06K 7/10257 arrangements for protecting the interrogation against piracy attacks computer security in general G06F21/00; jamming of communication, countermeasures H04K3/00; secret communication H04K1/00
• CPC Class Codes: H04K 1/02 by adding a second signal to make the desired signal unintelligible
• CPC Class Codes: H04L 2209/601 Broadcast encryption
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/0656 Pseudorandom key sequence combined element-for-element with data sequence, e.g. one-time-pad [OTP] or Vernam's cipher

Abstract

Methods and apparatus provide secure two-way (reader-to-tag and tag-to-reader) RFID communications. According to one aspect, a tag receives a noise-encrypted RF carrier signal from a reader and backscatter modulates it with tag information. Eavesdroppers cannot extract the tag information from the backscattered signal because it is masked by the noise encryption.

Claims

1. An RFID reader for communicating with RFID tags, the reader comprising:

a signal generator configured to generate an RF carrier signal and to modulate the RF carrier signal with a noise encryption waveform; and

an antenna configured to transmit the noise-encrypted RF carrier signal to the tags.

2. The reader of claim 1, wherein:

the signal generator includes

a voltage-controlled oscillator (VCO) operable to produce a carrier signal, and

a variable gain amplifier (VGA) having a first input configured to receive the carrier signal from the VCO and a second gain control input configured to receive an amplitude modulation signal, said VGA operable to generate an amplitude-modulated carrier signal, and

the amplitude modulation signal is configured to cause the VGA to noise-encrypt the RF carrier signal.

3. The reader of claim 2, wherein:

the VCO includes at least one of a phase and frequency control input configured to receive a corresponding phase/frequency modulation signal.

4. The reader of claim 1, wherein:

the noise encryption waveform includes an amplitude modulation component.

5. The reader of claim 4, wherein:

the noise encryption waveform further includes a frequency modulation component.

6. The reader of claim 4, wherein:

the noise encryption waveform further includes a phase modulation component.

7. The reader of claim 1, further comprising:

a processor configured to remove the noise encryption from a signal backscattered from at least one of the tags.

8. The reader of claim 7, wherein:

the noise encryption waveform includes an amplitude modulation component.

9. The reader of claim 8, wherein:

the noise encryption waveform further includes a frequency modulation component.

10. The reader of claim 8, wherein:

the noise encryption waveform further includes a phase modulation component.

11. An RFID reader, comprising:

means for generating an RF carrier signal and for modulating the RF carrier signal with a noise encryption waveform; and

means for transmitting the noise-encrypted RF carrier signal.

12. The reader of claim 11, further comprising:

means for removing the noise encryption from a signal backscattered from at least one RFID tag.

13. The reader of claim 11, wherein:

the noise encryption waveform includes an amplitude modulation component.

14. The reader of claim 13, wherein:

the noise encryption waveform further includes a frequency modulation component.

15. The reader of claim 13, wherein:

the noise encryption waveform further includes a phase modulation component.

16. A method for reading an RFID tag with an RFID reader, the method comprising:

modulating at the reader an RF carrier signal with a noise encryption signal to produce a noise-encrypted RF carrier signal; and

transmitting the noise-encrypted RF carrier signal to a tag.

17. The method of claim 16, further comprising:

singulating the tag from a plurality of tags.

18. The method of claim 16, wherein:

said modulating includes amplitude modulating the RF carrier signal.

19. The method of claim 18, wherein:

said modulating further includes frequency modulating the RF carrier signal.

20. The method of claim 18, wherein:

said modulating further includes phase modulating the RF carrier signal.

21. The method of claim 16, further comprising:

receiving at the reader a backscattered signal from the tag; and

removing the noise encryption from the backscattered signal.

22. The method of claim 21, wherein:

said modulating includes amplitude modulating the RF carrier signal.

23. The method of claim 22, wherein:

said modulating further includes frequency modulating the RF carrier signal.

24. The method of claim 22, wherein:

said modulating further includes phase modulating the RF carrier signal.