Google’s upcoming plans to replace third-party cookies with a less invasive ad targeted mechanism have a number of issues that could defeat its privacy objectives and allow for significant linkability of user behavior, possibly even identifying individual users.
“FLoC is premised on a compelling idea: enable ad targeting without exposing users to risk,” said Eric Rescorla, author of TLS standard and chief technology officer of Mozilla. “But the current design has a number of privacy properties that could create significant risks if it were to be widely deployed in its current form.”
Short for Federated Learning of Cohorts, FLoC is part of Google’s fledgling Privacy Sandbox initiative that aims to develop alternate solutions to satisfy cross-site use cases without resorting to third-party cookies or other opaque tracking mechanisms.
Essentially, FLoC allows marketers to guess users’ interests without having to uniquely identify them, thereby eliminating the privacy implications associated with tailored advertising, which currently relies on techniques such as tracking cookies and device fingerprinting that expose users’ browsing history across sites to advertisers or ad…