Retention and revocation of operation keys by a control unit
AssigneeTexas Instruments Incorporated
InventorJin-Meng HO
Life of this patent
Estimating the term…
Abstract
A control unit device in one disclosed embodiment includes a receiver and a memory that stores one or more operation keys and program instructions. The control unit further includes a processor coupled to the receiver and the memory. 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 selecting which of the one or more operation keys to retain in the memory based on, 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.
Claims21
A control unit device comprising:
- a receiver that receives signals;
- a memory that stores a control unit counter, 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:
- receive, using the receiver, a message including a predetermined number of bits of an encrypted key fob counter value, wherein the encrypted key fob counter value is encrypted by a first operation key corresponding to a first key fob device;
- generate an encrypted value of the control unit counter using the first operation key;
- determine whether the predetermined number of bits of the encrypted value of the key fob counter matches corresponding bits of the encrypted value of the control unit counter;
- and
- enter a revocation mode in response to receiving a revocation command, wherein, during a revocation mode period following entering the revocation mode, the control unit identifies which of the one or more operation keys stored in the memory are associated with key fob devices that perform an operation during the revocation mode period, retains the identified operation key(s) in the memory, and delete operation key(s) associated with key fob devices that do not perform an operation during the revocation mode period.
A control unit device comprising:
- a receiver;
- a memory that stores 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 selecting which of the one or more operation keys to retain in the memory based on, 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.
A system comprising:
- a first device that transmits a message, the first device comprising:
- a first memory that stores a first counter value and a first operation key;
- a first processor that encrypts the first counter value using the first operation key, the first operation key being associated with the first device;
- and
- a transmitter that transmits the message, the message including predetermined bits of the encrypted first counter value and a command data field indicating a command;
- and
- a second device that receives the message, the second device comprising:
- a receiver that receives the message transmitted by the first device;
- a second memory that stores one or more operation keys and a second counter value, the stored one or more operation keys including at least the first operation key;
- and
- a second processor that encrypts the second counter value using the first operation key and compares the predetermined bits of the encrypted first counter value to corresponding bits of the encrypted second counter value, wherein the second processor causes the second device to perform the command indicated by the command data field when the predetermined bits of the encrypted first counter value matches the corresponding bits of the encrypted second counter value.
Dependencies are inferred from the claim text.