  Low-energy Bluetooth devices have become ubiquitous and widely used for
different applications. Among these, Bluetooth trackers are becoming popular as
they allow users to track the location of their physical objects. To do so,
Bluetooth trackers are often built-in within other commercial products
connected to a larger crowdsourced tracking system. Such a system, however, can
pose a threat to the security and privacy of the users, for instance, by
revealing the location of a user's valuable object. In this paper, we introduce
a set of security properties and investigate the state of commercial
crowdsourced tracking systems, which present common design flaws that make them
insecure. Leveraging the results of our investigation, we propose a new design
for a secure crowdsourced tracking system (SECrow), which allows devices to
leverage the benefits of the crowdsourced model without sacrificing security
and privacy. Our preliminary evaluation shows that SECrow is a practical,
secure, and effective crowdsourced tracking solution
