DIT — enabling de-identified data collection on WhatsApp

This post introduces De-identified Telemetry (DIT) for WhatsApp, a novel system designed to collect usage, reliability, and performance data while significantly enhancing user privacy. DIT leverages an Anonymous Credential System (ACS) and Verifiable Oblivious Pseudorandom Functions (VOPRFs) to authenticate data without the server learning its origin, thereby minimizing metadata tied to specific individuals. The post details the technical implementation, including the two-step logging workflow, curve choices, unlinkability guarantees, re-identifiability mitigation, rate limiting, and communication cost optimizations, showcasing a significant step in privacy-preserving data collection for operational insights.