How We’re Building Scam Alert on WhatsApp With End-to-End Encryption and Verifiability Guarantees

WhatsApp is rolling out Scam Alert in Beta, an optional feature that runs an on-device ML model to detect likely scam messages from non-contacts, with no message content leaving the device unless the user chooses to report. Warning and user-action telemetry is aggregated via a confidential federated analytics pipeline built on Trusted Execution Environments (TEEs) and differential privacy, so only anonymous, noisy aggregates reach Meta. Model versions are published to a third-party append-only transparency ledger and signed via Cloudflare Ed25519 keys before deployment, preventing targeted model delivery. Client-side transparency logs let users inspect what the model flagged, and an expanded Bug Bounty program lets external researchers audit the model weights and privacy pipeline.

Source: https://engineering.fb.com/2026/08/12/security/how-were-building-scam-alert-whatsapp. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.