RFID tags with digital signature subportions

• US 9,911,018 B1
• Filed: 09/18/2013
• Issued: 03/06/2018
• Est. Priority Date: 01/12/2012
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Heinrich, Harley, Arnstein, Lawrence F., Diorio, Christopher J.
• Primary Examiner(s): Terrell, Emily C
• Application Number:
  US14/030,854
• Time in Patent Office: 1,630 Days
• Field of Search: 340 101- 1052, 380277-286, 380 44- 46, 380 29, 380255-270, 713180, 713171, 713176
• CPC Class Codes: G06K 19/07318 by hindering electromagnetic reading or writing jamming of communication, counter-measures H04K3/00; secret communication H04K1/00
• CPC Class Codes: G06K 19/10 at least one kind of marking being used for authentication, e.g. of credit or identity cards verification of coded identity or credit cards in mechanisms actuated by them G07F7/12
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/0866 involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

A Radio Frequency Identification (RFID) tag integrated circuit (IC) stores a subportion of a digital signature and a subportion indicator that may be used to authenticate the IC, a tag including the IC, and/or an item associated with the tag. The subportion of the digital signature is generated, at least in part, by applying a cryptographic function to an identifier associated with the IC, the tag, and/or the item.

Claims

1. A method for digitally signing a Radio Frequency Identification tag, comprising:

retrieving a tag instance identifier (TII) and a key;

generating a digital signature from at least the TII and the key;

selecting a subportion of the digital signature;

determining a subportion indicator that identifies the selected subportion from a set of two or more subportions of the digital signature; and

forming an item instance identifier (III) from at least the selected subportion and the subportion indicator.

2. The method of claim 1, further comprising forming an item serial number from an item class identifier (ICI) and the III.

3. The method of claim 2, wherein the ICI is null.

4. The method of claim 1, further including storing the III in an IC of the tag.

5. The method of claim 1, further comprising generating the digital signature using a cryptographic algorithm.

6. The method of claim 1, further comprising one of:

retrieving the subportion indicator from a memory;

retrieving the subportion indicator from a command, and

retrieving the subportion indicator from a network.

7. The method of claim 1, further comprising:

determining whether the selected subportion of the digital signature is unique; and

if the selected subportion is not unique then selecting another subportion.

8. The method of claim 7, further comprising referencing a network database to determine whether the selected subportion is unique.

9. The method of claim 1, further comprising forming the III at one of:

a time of IC manufacture;

a time of tag manufacture;

a time of label manufacture;

a time when the tag is associated with an item;

expiration of a timer;

a power-up of the tag IC;

upon responding to a reader command;

prior to backscattering an item serial number to a reader; and

a processing block of the tag IC performing an operation.

10. A method for determining the authenticity of a Radio Frequency identification tag at an RFID reader, the method comprising:

receiving a tag instance identifier (TII) and an item instance identifier (III) from the tag;

retrieving a key from one of a memory, a command, and a network;

retrieving a subportion indicator from the II;

generating at least one of;

a verification III by encrypting at least the III with the key and selecting a subportion of the verification III indicated by the subportion indicator; and

a verification code by decrypting at least the Ill with the key and the subportion indicator;

comparing at least one of;

the verification III with the III; and

the verification code with the TII; and

determining the authenticity of the tag based on the comparison.

11. The method of claim 10, further comprising encrypting and decrypting using a cryptographic algorithm.

12. The method of claim 10 wherein the key is one of a public key and a private key.

13. The method of claim 10 wherein the authenticity determination is performed by one of a reader and a networked processor.

14. The method of claim 10, further comprising determining the integrity of the III based on the comparison.

15. A Radio Frequency Identification (RFID) integrated circuit (IC) comprising:

a memory storing a tag instance identifier (TII); and

a processing block configured to;

retrieve the TII and a key;

generate a digital signature from at least the TII and the key;

select a subportion of the digital signature;

determine a subportion indicator that identifies the selected subportion from a set of two or more subportions of the digital signature; and

form an item instance identifier (III) from at least the selected subportion and the subportion indicator.

16. The IC of claim 15, wherein the processing block is further configured to form an item serial number from an item class identifier (ICI) and the III.

17. The IC of claim 15, wherein the processing block is further configured to store the III in the memory.

18. The IC of claim 15, wherein the processing block is further configured to generate the digital signature using a cryptographic algorithm.

19. The IC of claim 15, wherein the processing block is further configured to retrieve the subportion indicator from one of the memory and a command.

20. The IC of claim 15, wherein the processing block is further configured to form the III at one of:

a time of IC manufacture;

a time of tag manufacture;

a time of label manufacture;

a time when the IC is associated with an item;

expiration of a timer;

a power-up of the IC;

upon responding to a reader command;

prior to backscattering an item serial number to a reader; and

upon performing an operation.