One-Way Key Fob and Vehicle Pairing Verification, Retention, and Revocation

• US 20160218870A1
• Filed: 04/04/2016
• Published: 07/28/2016
• Est. Priority Date: 08/30/2012
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Ho, Jin-Meng
• Granted Patent: US 9,698,980 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60R 25/10 actuating a signalling device
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G07C 9/20 involving the use of a pass
• CPC Class Codes: H04L 2209/84 Vehicles
• CPC Class Codes: H04L 9/0827 involving distinctive intermediate devices or communication paths network architectures or network communication protocols using different networks H04L63/18
• CPC Class Codes: H04L 9/0861 Generation of secret information including derivation or calculation of cryptographic keys or passwords
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage
• CPC Class Codes: H04L 9/3226 using a predetermined code, e.g. password, passphrase or PIN network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L63/083
• CPC Class Codes: H04L 9/3268 using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]

Abstract

Embodiments of the invention provide methods for key fob to control unit verification, retention, and revocation. After an initial pairing between a key fob and a control unit, the devices share a secret operation key (OpKey). For verification, the key fob sends the 8 lowest-order bits of a 128-bit counter and some bits of an AES-128, OpKey encrypted value of the counter to the control unit. For key revocation and retention, the control unit is prompted to enter an OpKey retention and revocation mode. Subsequently, each of the remaining or new key fobs is prompted by the user to send a verification message to the control unit. When the control unit is prompted to exit the OpKey retention and revocation mode, it retains the OpKeys of only the key fobs that sent a valid verification message immediately before entering and exiting the OpKey retention and revocation mode.

Claims

1-18. -18. (canceled)

19. A key fob device, comprising:

a transmitter configured to transmit signals to a control unit;

a memory configured to store a key fob counter and an operation key (OpKey); and

a processor coupled to said transmitter and memory, the processor configured to;

generate an AES-128 OpKey-encrypted value of the key fob counter;

transmit a command comprising a predetermined number of lowest-order bits of the key fob counter and a predetermined number of bits of the AES-128 OpKey-encrypted value of the key fob counter to the control unit;

transmit to the control unit a command to enter a revocation mode, wherein OpKeys associated with a first set of key fobs that operate during the revocation mode are retained and all other OpKeys associated with a lost key fob that does not perform an operation during the revocation mode period are deleted.

20. The key fob device of claim 19, wherein the predetermined number of lowest-order bits of the key fob counter is 8 bits.

21. The key fob device of claim 19, wherein the key fob counter is a 128-bit counter.

22. The key fob device of claim 19, the processor further configured to:

increment the key fob counter by one after transmitting the command to the control unit.

23. A control unit device, comprising:

a receiver configured to receive signals from a key fob;

a memory configured to store a control unit counter and an operation key (OpKey); and

a processor coupled to said receiver and memory, the processor configured to;

receive, from the key fob, a message comprising a predetermined number of bits of an AES-128 OpKey-encrypted value of a key fob counter;

generate an AES-128 OpKey-encrypted value of the control unit counter;

verify whether or not the predetermined number of bits of an AES-128 OpKey-encrypted value of a key fob counter matches the predetermined number of bits from the AES-128 OpKey-encrypted value of the control unit counter;

entering an revocation mode, wherein only a plurality of OpKeys received before exiting the revocation mode are retained and

delete all other OpKeys.

24. The control unit device of claim 23, the processor further configured to:

receive, from the key fob, a chosen number of lowest-order bits of the key fob counter; and

update the control unit counter based on the received bits and the corresponding bits of the control unit counter before generating an AES-128 OpKey-encrypted value of the control unit counter.

25. The control unit device of claim 24, wherein the chosen number of lowest-order bits of the control unit counter is 8 bits.

26. The control unit device of claim 23, the processor further configured to:

initiate a control operation if the predetermined number of bits of an AES-128 OpKey-encrypted value of the key fob counter matches the predetermined number of bits from the AES-128 OpKey-encrypted value of the control unit counter.

27. The control unit device of claim 23, wherein the control unit counter is a 128-bit counter.

28. The control unit device of claim 24, the processor further configured to:

restore the control unit counter to a value before the update after failing to verify that the predetermined number of bits of an AES-128 OpKey-encrypted value of the key fob counter matches the predetermined number of bits from the AES-128 OpKey-encrypted value of the control unit counter.

29. The control unit device of claim 23, wherein the message further comprises a data field that identifies a command to be executed by the control unit.