A tracking device can provide a hashed identifier to a mobile device, for instance within an advertisement packet. The mobile device can query each of a plurality of entities with the hashed identifier to identify an entity associated with the hash key used to generate the hashed identifier. In some embodiments, the mobile device can query a centralized key server, which in turn can query the plurality of entities to identify the entity associated with the hash key. The mobile device can then receive a public key from the identified entity, can determine a location of the mobile device, and can encrypt the location with the public key. The mobile device can then provide the hashed identifier and the encrypted location to the identified entity, which can provide the encrypted location to an owner of the tracking device for decryption using a private key corresponding to the public key.