Researchers develop a protocol to secure AirTags against stalking while maintaining privacy, aiming to improve on Apple's system of rotating public identifiers
The new research shifts the discussion from tuning notifications toward whether the underlying identifier design can better balance location privacy with abuse detection. It follows the researchers’ proposed privacy-preserving anti-stalking protocol and targets a limitation of rotating public identifiers.
First-order effects
Apple and tracker-system designers gain a concrete technical alternative to evaluate against identifier rotation, rather than relying solely on alert timing and audible warnings.
Researchers and privacy advocates get a framework for assessing whether anti-stalking protections can be strengthened without making item-tracking identifiers broadly linkable.
Second-order effects
If adopted or validated, the approach could force competing item-finder networks to compare their privacy protections at the protocol level, not just through user-facing safety features.
A more robust technical standard could reduce the trade-off between protecting owners’ location data and helping potential stalking targets identify unwanted trackers.
Third-order effects
If this line of work is deployed across tracker ecosystems, anti-stalking safeguards may become a core interoperability and product-design requirement for dual-use location tools rather than a post-launch mitigation.
The outcome remains uncertain: a research protocol must still be tested for deployability, usability, and resistance to misuse before it can displace existing safeguards.
The trend: Item-tracking platforms are moving toward privacy-preserving safety architectures that address abuse risks in the network protocol itself.
An even more cryptographically private approach Apple (and Google and Tile etc) could take to reduce AirTag stalking/abuse while still maximizing the anonymity of legitimate devices. Also includes choice bonus content of @matthew_d_green just loving cryptography so much https://…
Really interesting application of secret sharing to airtag privacy. On short timescales devices are transient, indistinguishable and difficult to track. But after spending enough time in proximity to a particular device, you learn to identify it from the crowd.
The solution we developed uses “secret sharing.” Each device has a long-lived secret, but instead of broadcasting that, it broadcasts a “share” of its secret every few minutes. If any receiver obtains a sufficient number of shares, they can put them together and detect the tag.
(Apple and Google are working on a joint IETF standard that will mandate this lower level of privacy. Here's the relevant section.) https://datatracker.ietf.org/ ... [image]
Two years later, Apple introduced the AirTag. At this point they noticed a problem: people were using location trackers to stalk victims, by placing them on victims' possessions or cars. This led to several murders. https://arstechnica.com/...
TL;DR thread. When Apple launched their “Find My” system for lost devices in 2019, they designed a clever solution to keep bad actors (including Apple) from tracking users. This works by making devices change their broadcast identifier every 15 minutes. https://blog.cryptographye…
Article on some new research that finds ways to balance privacy and stalker detection for AirTags and other location trackers. This is a collaboration with my students @gabrie_beck, Harry Eldridge and colleagues Abhishek Jain and Nadia Heninger. https://www.wired.com/...
There is a lot more to this, obviously. For a full description of the work, here is our pre-print: https://eprint.iacr.org/... Even if this is not the solution Apple et al. adopt, I hope they will consider improving the privacy guarantees of these devices. //fin