RFID tag authentication with public-key cryptography

• US 8,941,469 B1
• Filed: 06/07/2011
• Issued: 01/27/2015
• Est. Priority Date: 06/14/2010
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Diorio, Christopher J., Cooper, Scott A.
• Primary Examiner(s): Nguyen, Nam V
• Application Number:
  US13/155,057
• Time in Patent Office: 1,330 Days
• Field of Search: 340 101- 105, 380/45, 380/25, 713/176, 713/180, 713/169, 705/76
• US Class Current: 340/10.1
• CPC Class Codes: G06Q 30/0185 Product, service or business identity fraud
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/3271 using challenge-response
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication

Abstract

An authentication method includes RFID readers authenticating RFID tags using public-key cryptography. A tag manufacturer or other legitimate authority produces a tag private-public key pair and stores the tag private key in externally unreadable tag memory and the tag public key in externally readable tag memory. The authority produces a master private-public key pair and distributes the master public key to readers in the field. The authority generates a tag-specific electronic signature based on at least the tag public key and the master private key and stores this signature in externally readable tag memory. A reader authenticates the tag by retrieving the tag public key and electronic signature from the tag, verifying the authenticity of the tag public key using the master public key and the electronic signature, challenging the tag, receiving a response from the tag to the challenge, and verifying the response using the tag public key.

Claims

1. A method for a Radio Frequency Identification (RFID) reader to authenticate an RFID tag, the method comprising:

retrieving a tag public key (TPK), an item identifier (II), and an electronic signature (ES) from the tag, the ES computed over at least the TPK and the II;

retrieving a signing-authority public key (SAPK) associated with the ES from a signing authority;

verifying, using the SAPK and the ES, the TPK and the II;

challenging the tag with a challenge;

receiving a response from the tag; and

authenticating the tag by verifying the response using the TPK.

2. The method of claim 1, wherein the II comprising one or more of:

a tag identifier (TID), a unique item identifier (UII), an electronic product code (EPC), and a serialized trade identification number (SGTIN).

3. The method of claim 1, wherein the ES is generated from the TPK, the II, and a signing-authority private key (SAPRK) associated with the SAPK.

4. The method of claim 1, wherein the challenge includes a random number and verifying the response includes decrypting the response using the TPK.

5. The method of claim 1, wherein the challenge includes a random number encrypted using the TPK and verifying the response includes comparing the response with the random number.

6. The method of claim 1, further comprising receiving an initial value (IV) from the tag, the initial value generated by the tag from at least a tag random number and a tag private key (TPRK).

7. The method of claim 6, wherein the challenge includes a random number derived at least in part from the IV.

8. The method of claim 1, wherein the challenge is generated from at least a reader random number and a tag random number.

9. The method of claim 1, wherein the RFID tag stores a tag private key (TPRK) associated with the TPK.

10. The method of claim 9, further comprising:

causing the tag to form its response from at least the challenge and the TPRK.

11. The method of claim 9, further comprising:

causing the tag to form its response from at least the challenge, the TPRK, and a tag random number using a cryptographic algorithm.

12. The method of claim 9, wherein the TPK is stored in a readable memory of the tag and the TPRK is stored in an unreadable memory of the tag.

13. The method of claim 1, wherein challenging the tag precedes retrieving the TPK.

14. The method of claim 1, wherein receiving the response includes reading the response from a tag memory.

15. A Radio Frequency Identification (RFID) reader system for authenticating an RFID tag, the system comprising:

an RFID reader configured to;

retrieve a tag public key (TPK), an item identifier (II), and an electronic signature (ES), the ES computed over at least the TPK and the II, from the tag;

retrieve a signing-authority public key (SAPK) associated with the ES from a signing authority;

verify, using the SAPK and the ES, the TPK and the II;

challenge the tag with a challenge;

receive a response from the tag; and

authenticate the tag by verifying the response using the TPK.

16. The RFID reader system of claim 15, wherein the II comprises one or more of:

a tag identifier (TID), a unique item identifier (UII), an electronic product code (EPC), and a serialized trade identification number (SGTIN).

17. The RFID reader system of claim 15, wherein the RFID reader is further configured to:

cause the tag to generate a tag random number;

receive at least one of the tag random number and a function of the tag random number from the tag; and

verify the response using at least a reader random number, one of the tag random number and the function of the tag random number, and the TPK.

18. The RFID reader system of claim 15, wherein the challenge includes a random number and verifying the response includes decrypting the response using the TPK.

19. The RFID reader system of claim 15, wherein the challenge includes a random number encrypted using the TPK and verifying the response includes comparing the response with the random number.

20. The RFID reader system of claim 15, wherein the TPK is stored in a readable memory of the tag and a tag private key (TPRK) associated with the TPK is stored in an unreadable memory of the tag.

21. The RFID reader system of claim 15, wherein challenging the tag precedes retrieving the TPK, and receiving the response includes reading the response from a tag memory.

22. A method for a Radio Frequency Identification (RFID) reader to authenticate an RFID tag, the method comprising:

retrieving a tag public key (TPK) and an item identifier (II) from the tag;

retrieving at least one of a first electronic signature (ES1) and a second electronic signature (ES2) from the tag, the ES1 and the ES2 computed over at least the TPK and the II;

retrieving at least one of a first signing-authority public key (SAPK1) associated with the ES1 from a first signing authority and a second signing-authority public key (SAPK2) associated with the ES2 from a second signing authority;

verifying the TPK and the II using at least one of;

the SAPK1 and ES1, and

the SAPK2 and ES2;

challenging the tag with a challenge;

receiving a response from the tag; and

authenticating the tag by verifying the response using the TPK.

23. The method of claim 22, wherein the II comprises one or more of:

a tag identifier (TID), a unique item identifier (UII), an electronic product code (EPC), and a serialized trade identification number (SGTIN).

24. The method of claim 22, wherein the ES1 is generated from the TPK, the II, and a first signing-authority private key (SAPRK1) associated with the SAPK1.

25. The method of claim 22, wherein the challenge includes a random number and verifying the response includes decrypting the response using the TPK.

26. The method of claim 22, wherein the challenge includes a random number encrypted using the TPK and verifying the response includes comparing the response with the random number.

27. The method of claim 22, wherein the first signing authority and the second signing authority are the same entity.