Building end-to-end security for Messenger

What this post added

This post details the technical implementation and challenges of enabling end-to-end encryption (E2EE) by default for Messenger personal conversations. It introduces the Labyrinth encrypted storage protocol for E2EE message history and discusses the cryptographic protocol for message transmission. Key technical challenges addressed include multi-device capability, feature support (e.g., using OHAI and Anonymous Credentials for sticker library searches), message history management with Labyrinth, and web support for E2EE.