Retention and revocation of operation keys by a control unit
First Claim
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1. A control unit device comprising:
- a receiver configured to receive signals;
a memory configured to store 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.
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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.
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Citations
13 Claims
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1. A control unit device comprising:
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a receiver configured to receive signals; a memory configured to store 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system comprising:
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a first device comprising; a first memory configured to store a first counter value and a first operation key; a first processor configured to encrypt the first counter value using the first operation key, the first operation key being associated with the first device; and a transmitter configured to transmit a message, the message including predetermined bits of the encrypted first counter value and a command data field indicating a command; and a second device comprising; a receiver configured to receive the message when transmitted by the transmitter of the first device; a second memory configured to store 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 configured to encrypt the second counter value using the first operation key and to compare 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. - View Dependent Claims (10, 11, 12, 13)
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Specification