WhatsApp Security Whitepaper [pdf]

whatsapp.com

92 points·frankpf··9 comments

From what I can tell, the main difference between this and what Signal was using as of December is:

- WhatsApp uses AES-256 instead of AES-128 (both are CBC mode)

- WhatsApp uses HMAC-SHA-256 instead of HMAC-SHA-1

I think everything else is the same. (I need to re-read the Signal Protocol specification later today to make sure.)

There is no difference, WhatsApp and Signal both use the Signal Protocol, and the same code: https://github.com/whispersystems/libsignal-protocol-java

Oh, excellent.

(Last I checked it was still AES-128 and SHA-1, but that was before the name change and I wasn't sure if it had changed. Glad to hear it has.)

The WhatsApp paper also mentions that they are using AES-GCM for message transit (Client A → WhatsApp server, I guess).

It's nice to see decent security turned into a product desired by the users! I wonder which big platform is going to adopt this next :)

Is there any open-source Linux desktop implementation?

No but there's a desktop web front-end which relays through your smartphone. https://web.whatsapp.com

Do they use pinning for the Transport Layer? Apple seems to do that in their newer versions. Or is their some reason why they should not?

end-to-end encryption protocol haa?