88: No Way Out - Engineering Message History Only You Can Read

How do you add end-to-end encryption to a messenger that people have already been using for years, without taking away the message history they expect to be there? Emma Connor works on the team behind Labyrinth, Messenger's encrypted storage protocol. We get into where the encryption keys actually live, which turns out to be nowhere near Meta, and why a six-digit PIN is far harder to attack than six digits ought to be. Emma also explains the hardware security modules that Meta deliberately locked itself out of, what happens when you lose a device and want it cut out of your account, how key transparency lets you verify who you are talking to without having to trust us, and why Labyrinth 1.1 moved to post-quantum cryptography. All of this and more is discussed in this episode.

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Links

• Opaque Rust Crate - https://crates.io/crates/opaque-ke

• Labyrinth 1.1: Making End-to-End Encrypted Backups Even More Reliable - https://engineering.fb.com/2026/05/11/security/labyrinth-1-1-end-to-end-encrypted-e2ee-backups-more-reliable/

• The Labyrinth Encrypted Message Storage Protocol - https://engineering.fb.com/wp-content/uploads/2026/05/Minos-Updates-2026-Encrypted-Backups-White-Paper.pdf

• MTP E54: Building Key Transparency at WhatsApp - https://pca.st/orlsiq1l

• MTP E65: Getting Ready for Post-Quantum Cryptography - https://pca.st/4klppivy

• NTS: Authenticated Time at Meta - https://engineering.fb.com/2026/10/06/production-engineering/nts-authenticated-time-at-meta/

Timestamps

• Intro 0:06

• Introduction Emma 2:25

• The Complexity of End-to-End Encryption 3:42

• User Expectations and Mental Models 5:35

• The Labyrinth System Overview 7:17

• Key Management and Security 7:54

• Rate-limiting passcode guesses 13:01

• Evolution of Backup Systems 16:45

• Rolling Out New Storage Protocols 17:07

• Ensuring Data Integrity During Migration 18:34

• Multi-Device Support Challenges 18:48

• Building Custom Cryptography Solutions 20:20

• Revoking Device Access 23:56

• Labyrinth 1.1: 26:24

• Preparing for Quantum Resistance 29:20

• Outro 36:16