A tracking device can securely communicate with a secondary device by generating a hash value based on the identity of the tracking device. If the secondary device cannot resolve the hash value, the hash value can be provided to a tracking server, such as a cloud server, for resolving the hash value. Upon resolving the hash value, the tracking server can store a location of the tracking device in association with the identity of the tracking device. To preserve power, the secondary device can activate location-detection functionality (such as a GPS receive) only in response to the detection of movement of the tracking device, can obtain location information, and can de-activate the location-detection functionality upon providing the location information to the tracking server. The tracking server can associate one or both of a previous location and the current location information based on movement of the tracking device.