One embodiment of the present invention provides a smart lock-and-key system. The smart lock-and-key system can include a smart lock corresponding to a lock identifier and a smart key capable of locking and unlocking the smart lock. The smart key can include a first communication interface for communicating with the smart lock and a second communication interface for communicating with a mobile computing device. The smart key can be configured to obtain the lock identifier and receive, from the mobile computing device, an operation command based on the obtained lock identifier.