Security system for a moveable barrier operator
AssigneeThe Chamberlain Group, Inc.
InventorJames J. Fitzgibbon
Life of this patent
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Abstract
Electronic systems are provided for secure actuation of a remote device such as a moveable barrier operator. The systems address the “man in the middle” problem of persons intercepting and duplicating radio frequency signals from a control device by introducing timing parameters into a bidirectional communication sequence between at least two devices.
Claims35
A method of operation by a first device communicating with a second device to effect an action by the second device, the method comprising:
- transmitting from the first device a first encrypted message that includes at least a first fixed code and a first changing code;
- receiving by the first device a response from the second device, wherein the response comprises a second encrypted message including a second fixed code and a second changing code that is independent from the first changing code;
- validating by the first device the response by comparing the second fixed code and the second changing code to second stored code values;
- in response to validating the response, transmitting by the first device a third encrypted message including at least the first fixed code and a changed version of the second changing code, wherein the third encrypted message is configured to effect performance of an action by the second device.
An apparatus configured to communicate with a second device to effect an action by the second device, the apparatus comprising:
- a controller circuit;
- a transmitter in operative communication with the controller circuit;
- a receiver in operative communication with the controller circuit;
- a user input device in operative communication with the controller circuit;
- wherein the controller circuit is configured to:
- in response to detecting an input at the user input device, control the transmitter to transmit a first encrypted message that includes at least a first fixed code and a first changing code;
- receive through the receiver a response from the second device, wherein the response comprises a second encrypted message including a second fixed code and a second changing code that is independent from the first changing code;
- validate the response by comparing the second fixed code and the second changing code to second stored code values from a memory circuit;
- in response to validating the response, control the transmitter to transmit a third encrypted message including at least the first fixed code and a changed version of the second changing code, wherein the third encrypted message is configured to effect performance of an action by the second device.
A non-transitory computer readable medium having stored thereon instructions that when executed by a controller circuit of a first device cause the controller circuit to perform operations comprising:
- transmitting from the first device a first encrypted message that includes at least a first fixed code and a first changing code;
- receiving by the first device a response from the second device, wherein the response comprises a second encrypted message including a second fixed code and a second changing code that is independent from the first changing code;
- validating by the first device the response by comparing the second fixed code and the second changing code to second stored code values;
- in response to validating the response, transmitting by the first device a third encrypted message including at least the first fixed code and a changed version of the second changing code, wherein the third encrypted message is configured to effect performance of an action by the second device.
Dependencies are inferred from the claim text.