How does WhatsApp implement encrypted group chats? And are they secure? @malb.bsky.social, @bedow.bsky.social and myself were keen to figure this out. After two years of reverse-engineering, analysis and a few too many proofs, I presented our work at Eurocrypt earlier today. So, what did we learn?
Formal Analysis of Multi-Device Group Messaging in WhatsApp
WhatsApp provides end-to-end encrypted messaging to over two billion users. However, due to a lack of public documentation and source code, the specific security guarantees it provides are unclear. Se...
ia.cr