Batteryless lock with trusted time
View Patent ↗An electronic lock controller comprises a trusted time provider, a near field communication transceiver, and a logic processor. The trusted time provider provides a trusted time value. The near field communication transceiver receives power and a digital credential from an operator-side interface device. The logic processor produces an open or close command for an electromechanical lock based on the trusted time value and the digital credential. The electronic lock controller is powered solely by the near field communication transceiver.
1. An electromechanical lock assembly, comprising:
a mechanical lock; and
an actuator capable of locking and unlocking the mechanical lock; and
an electronic lock controller for controlling the actuator, the lock controller comprising:
a trusted time provider for supplying a trusted time value;
a near field communication transceiver capable of communicating with and inductively receiving power from an operator-side interface device; and
a logic processor capable of producing an open command for the actuator based on the trusted time value and a digital credential sent by an operator;
wherein—
the electronic lock controller is primarily powered by the near field communication transceiver, and not by a battery or wired grid connection; and wherein—
the digital credential is time-stamped and valid only during a bounded time window, and the operator receives the digital credential from a central server during the bounded time window, and
the trusted time provider comprises a register which updates a date/time reference based on each digital credential received, thereby providing a trusted “high water mark” time which increases monotonically with each operator interaction with the electromechanical lock assembly.
2. The electromechanical lock assembly of claim 1 , wherein the actuator is also powered by the near field communication transceiver.
3. The electromechanical lock assembly of claim 1 , wherein the trusted time provider is a transceiver which receives a time reference from a real time clock server when powered by the operator-side interface device.
4. The electromechanical lock assembly of claim 1 , further comprising an ambient light sensor, and wherein the trusted time provider increments a time or date value by counting day/night cycles with the ambient light sensor.
5. The electromechanical lock assembly of claim 1 , further comprising an energy scavenging system, and wherein the trusted time provider is a low-power timekeeper powered by the energy scavenging system.
6. The electromechanical lock assembly of claim 5 , wherein the energy scavenging system is a solar power cell.
7. The electromechanical lock assembly of claim 5 , wherein the energy scavenging system is a mechanical energy scavenger which receives power from building resonance or movement of the electromechanical lock.
8. An electronic lock controller, comprising:
a trusted time provider capable of providing a trusted time value;
a near field communication transceiver capable of communicating with and inductively receiving power from an operator-side interface device; and
a logic processor capable of producing an open command for an electromechanical lock based on the trusted time value and a digital credential sent by an operator;
wherein the lock controller is primarily powered by the near field communication
transceiver, and not by a battery or wired grid connection; and wherein—
the digital credential is time-stamped and valid only during a bounded time window, and the operator receives the digital credential from a central server during the bounded time window, and
the trusted time provider comprises a register which updates a date/time reference based on each digital credential received, thereby providing a trusted “high water mark” time which increases monotonically with each operator interaction with the electromechanical lock controller.
9. The electronic lock controller of claim 8 , wherein the trusted time provider is chosen from a plurality of trusted time provider options of which the electronic lock controller is capable.
10. The electronic lock controller of claim 8 , wherein the trusted time provider is chosen according to instructions carried in the digital credential.
11. The electromechanical lock assembly of claim 8 , wherein each digital credential is valid only for a predetermined number of uses, after which a new digital credential must be downloaded.
12. The electromechanical lock assembly of claim 11 , wherein the predetermined number of uses is specified by the digital credential.
13. The electronic lock controller of claim 8 , further comprising a low energy timer capable of running for a finite time period on power received from the near field communication transceiver; and wherein the trusted time is updated according to the time elapsed on the timer.
14. The electronic lock of claim 13 , wherein the electronic lock controller requests a certified time via the interface device if a preset time has elapsed on the timer when the logic processor is powered by the near field communication transceiver.
15. The electronic lock controller of claim 8 , further comprising an energy storage medium which gradually decays at a predictable rate once energized, and wherein the trusted time is updated with an elapsed time calculated from the rate and amount of decay of the energy storage medium.
16. A method for operating an electromechanical lock, the method comprising:
inductively powering the electromechanical lock from an operator-side near field communication capable interface device placed in proximity with the electromechanical lock;
connecting with and receiving a digital credential from the interface device;
determining a trusted time using power received from the interface device;
evaluating the digital credential in light of the trusted time, wherein the digital credential is time-stamped and valid only during a bounded time window, and the operator receives the digital credential from a central server during the bounded time window,
engaging or disengaging the lock if evaluation of the digital credential indicates that the credential is valid; and
updating a date/time reference in a register based on each digital credential received, thereby providing a trusted “high water mark” time which increases monotonically with each operator interaction with the electromechanical lock.
17. The method of claim 16 , further comprising:
transmitting a transaction code to the interface device; and
receiving a certified time code retrieved by the interface device from a real time clock server, the certified time code including a time value and a certificate dependent on the transaction code; and
wherein determining the trusted time comprises evaluating the certified time code for authenticity to produce the trusted time.
18. The method of claim 17 , wherein the real time clock server is located at a remote location such as a broadcasting station or an artificial satellite.
19. The method of claim 17 , wherein the real time clock server comprises one of a local device in a secure area, a portable device carried by the user, or a web server.
20. The method of claim 17 , wherein the interface device is a dedicated hardware device designed to operate with the electromechanical lock.
21. The method of claim 17 , wherein the interface device is a multipurpose hardware device running dedicated software designed to operate the electromechanical lock.
22. The method of claim 17 , wherein determining a trusted time comprises the electronic lock retrieving a time from a trusted time server using power received from the interface device.
23. The method of claim 22 , wherein the trusted time server is a local device in a secure location or carried by a user.
24. The method of claim 22 , wherein the trusted time server is a remote device such a satellite or web server.
25. The method of claim 16 , wherein the trusted time is determined using a method specified by the digital credential.
26. The method of claim 16 , wherein the trusted time is retrieved from a real time clock server designated by the digital credential.