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

Engineering at Meta

Aug 12, 2026

8/12/2026

Non-Targetable On-Device ML Experiments With Cryptographic Signatures Ledger Verification And Group Size Safeguards

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

Science, Technology & Innovation · Aug 12, 2026

WhatsApp proposes combining publicly logged, Cloudflare-signed model artifacts with client-side hash verification, anonymous delivery, device-controlled experiment assignment, minimum group sizes, k-anonymous analytics, and user/researcher auditing to prevent or expose person-specific model targeting.


8/12/2026

Privacy-Preserving Aggregate Quality Monitoring Is Enforceable By Client-Side Auditable Protocols That Refuse Noncompliant Data Collection

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

Science, Technology & Innovation · Aug 12, 2026

Meta and WhatsApp’s Scam Alert measurement system uses client-enforced, privacy-preserving aggregation—local noisy counts, randomized anonymous transmission, TEEs, differential privacy, cohort thresholds, OHTTP, and anonymous credentials—with fail-closed verification to support auditable quality monitoring without message- or user-level telemetry.


8/12/2026

WhatsApp Scam Alert Uses On-Device Privacy-Preserving Inference With User Opt-In And Limited Data Sharing For Improvement

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

Science, Technology & Innovation · Aug 12, 2026

WhatsApp’s Scam Alert uses an opt-in, on-device model to flag suspicious messages from non-contacts while preserving end-to-end encryption: alerts remain visible only to recipients, no messages or detection events are automatically shared, and users may separately consent to send limited feedback data for model improvement. The feature is in limited beta, so its detection performance is not yet established.