WhatsApp Key Transparency

on YouTube ↗13m

" summary

WhatsApp describes a deployed key transparency system using the open-source Auditable Key Directory (AKD), publishing about 50,000 epochs so far and maintaining roughly 20 billion nodes in its Merkle trees with a publish cadence of every five minutes and ~100,000 new entries per epoch. Guarantees rely on a single internally signed root (no external quorum yet), history checking is unresolved so they use dual lookup fallbacks, and audit proofs currently reach hundreds of megabytes.

AI-written summary · about

" chapters (4)

1. 0:00The problem with key security
2. 3:24Key transparency overview
3. 6:48Deployment challenges
4. 10:25Implementation and open source

" related talks

• 19mPrekey Pogo: Investigating Security and Privacy Issues in WhatsApp's Handshake MechanismGabriel Karl Gegenhuber, Philipp É. Frenzel, Maximilian Günther, Aljosha Judmayer · 19th USENIX WOOT Conference on Offensive Technologies (WOOT '25)
• 19mBuilding private productsAleksander Bello · Product @Scale Spring 2022
• 23mWhatsApp Private ProcessingKevin Hui, Yunqi Li, Elizabeth Li, Henry Wang, Varun Patil · Confidential Computing Summit 2026
• 23mReverse Engineering WhatsApp Encryption for Chat Manipulation and MoreRoman Zaikin, Oded Vanunu · Black Hat USA 2019
• 24mWhatsApp with privacy? Privacy issues with IM E2EE in the Multi-device settingTal A. Be'ery · WOOT '24
• 40mEnd-to-end encryption: Behind the scenesMartin Kleppmann, Diana Vasile · Strange Loop 2016
• 01h 01mKey transparency: Blockchain meets NoiseSocketAleksey Ermishkin · HighLoad++ 2017
• 26mOperationalizing Key Management for Regulatory Compliance and Emergency ResponseSwetha Srinivasan · SREcon26 Americas