Rust at Scale: An Added Layer of Security for WhatsApp

Post by londons_explore » Wed, Jan 28, 2026, 5:22 PM UTC

antonvs wrote: post #59

Fripplebubby wrote: post #48

Earlier quoted context omitted.

This is not true. The IETF draft is explicit that E2EE means that the message cannot be read by any party other than the sender and the intended receiver. When companies like Meta claim they support E2EE, this is what they claim. There are no tricky semantics or legalese at play here.

It's not entirely accurate to say "any party other than the sender and the intended receiver," since the messaging app running on the user's device can read the messages. Something like "any third party (other than the app vendor)" would be more accurate. Without actually analyze app behavior, it comes down to trusting that the vendor doesn't do anything nefarious.

Post by galangalalgol » Wed, Jan 28, 2026, 5:27 PM UTC

jraph wrote: post #71

londons_explore wrote: post #66

> over 3 billion people to message securely each and every day. Whatsapp is a chat application with 3 billion daily active users. For those of you in the US (where Whatsapp is seldom used), this is a fact worth remembering. If you want to build products for the rest of the world, you need to know how those users think and breathe - and for 3 billion of them, Whatsapp is how they talk.

What one should do about this? I mean, beside working on lowering that number. (Asking as a European who quite stubbornly refuses to install it - there are dozens of us. Dozens!) Edit: please don't participate in making WhatsApp even more inescapable as it is today.

Post by charcircuit » Wed, Jan 28, 2026, 5:27 PM UTC

marisen wrote: post #4

nevi-me wrote: post #3

> We believe that this is the largest rollout globally of any library written in Rust. I suppose this is true because there's more phones using WhatsApp than there are say Windows 11 PCs. Given that WhatsApp uses libsignal, is it safe to assume that they haven't been using the Rust library directly?

WhatsApp doesn't use libsignal, and Android is already pretty Rusty and deployed more than WhatsApp around the world (not just smartphone. Tons of "embedded" use cases also run on custom Android)

Post by stingraycharles » Wed, Jan 28, 2026, 5:34 PM UTC

chinathrow wrote: post #62

justinlords wrote: post #58

The differential fuzzing approach is clever — way safer than a big-bang rewrite. Running both versions in parallel to catch edge cases before switching over is how you actually ship rewrites without breaking production. The 160k to 90k LOC drop is impressive, but the real engineering win is the validation strategy. On binary size, static linking with LTO should handle most of the bloat without needing custom stdlib b…

We really need an AI filter here on HN.

Post by harikb » Wed, Jan 28, 2026, 5:41 PM UTC

jraph wrote: post #71

londons_explore wrote: post #66

> over 3 billion people to message securely each and every day. Whatsapp is a chat application with 3 billion daily active users. For those of you in the US (where Whatsapp is seldom used), this is a fact worth remembering. If you want to build products for the rest of the world, you need to know how those users think and breathe - and for 3 billion of them, Whatsapp is how they talk.

What one should do about this? I mean, beside working on lowering that number. (Asking as a European who quite stubbornly refuses to install it - there are dozens of us. Dozens!) Edit: please don't participate in making WhatsApp even more inescapable as it is today.