Retention and revocation of operation keys by a control unit
AssigneeTexas Instruments Incorporated
InventorJin-Meng HO
Life of this patent
Estimating the term…
Abstract
An electronic key fob device, in one embodiment, includes a transmitter, a counter configured to provide a current counter value indicated by a plurality of bits, a memory configured to store an operation key, and a processor coupled to the transmitter and memory. The processor is configured to encrypt the current counter value using the operation key to produce an encrypted counter value, select a subset of the plurality of bits of the current counter value, transmit a message the includes the encrypted counter value and the subset of plurality of bits of the current counter value.
Claims19
An electronic key fob device, comprising:
- a transmitter;
- a counter configured to provide a current counter value indicated by a plurality of bits;
- a memory configured to store an operation key;
- and
- a processor coupled to the transmitter and memory, wherein the processor is configured to:
- encrypt the current counter value using the operation key to produce an encrypted counter value;
- select a subset of the plurality of bits of the current counter value;
- and
- transmit a message the includes the encrypted counter value and the subset of plurality of bits of the current counter value.
A control unit device comprising:
- a receiver;
- a memory configured to store one or more operation keys and program instructions;
- and
- a processor coupled to the receiver and the memory;
- wherein the program instructions are executable by the processor to cause the control unit device to, in response to a revocation command received by the receiver, perform a revocation process by:
- identifying at least some of the one or more operation keys as selected operation key(s) to retain in the memory by determining, for each of the one or more operation keys, whether the control unit receives a message encrypted by the operation key during the revocation process and identifying the operation key as a selected operation key if it is determined that a message encrypted by the operation key is received by the control unit during the revocation process;
- and
- after identifying the selected operation key(s), deleting from the memory any of the one or more operation keys that are not identified as a selected operation key.
Dependencies are inferred from the claim text.