However this comes with serious trade-offs. PGP lacks forward secrecy: if a key leaks, all past messages can be decrypted. Also IMAP offers no metadata privacy, anyone can see who you email and how often.
Signal and WhatsApp are likely a step ahead in terms of privacy with their double ratchet encryption (https://en.wikipedia.org/wiki/Double_Ratchet_Algorithm).
WhatsApp is closed source, so whatever they claim to can't be proven. And remember that both WhatsApp and Signal are legally required not to disclose to you whether they are spying on you or not.
E2E only requires a correctly-designed client, not a correctly-designed server.
Since any binary can always be deobfuscated, deliberately putting in a backdoor in the client would be an extremely risky PR move, especially in an app as big as WhatsApp, and one surely receiving lots of attention from security researchers.
Not to mention that OpenWhisperSystems (the creators of Signal) worked with Meta on their E2E implementation, and if you don't trust them to do right, you shouldn't trust anybody.
Let's face it, people over here just don't like Meta and love to spread FUD about them.
If you live in an authoritarian state with a track record of spying on individual citizens, and without legal protection for the privacy of foreign citizens, it's legitimate to decide not to trust a company like Meta headquartered in the USA.
That is not strictly true. It is possible to reverse-engineer the client. It's unlikely that anyone will find the motivation to do so, but there's no law of physics that says they can't. You can theoretically review the code that is running on your device - it's just harder than with an open source reproducible build.
It's called punching upwards.
>Since any binary can always be deobfuscated, deliberately putting in a backdoor in the client would be an extremely risky PR move, especially in an app as big as WhatsApp, and one surely receiving lots of attention from security researchers
Correct me if I'm wrong, but can't a proprietary delivery mechanism such as the App or Play stores deliver a backdoored build to an individual device, then later autoupdate it to a clean one?
Are you talking about decompilation? This, is in general very difficult, and that's when the author and compiler don't want to stop you from doing it.
Go fire up jadx or ghidra or whatever you like and see if you can find the bits of code you know are there. Now try demonstrating that a bit of code isn't there.
Yep, don't like it. They already have proven to not be trustworthy by various privacy scandals in the past
its the rest of the account and metadata that is at risk
Not to mention, if you revoke a key (maybe because you lost your laptop and want to be proactive about security), without any authenticated timestamping service in the mix, all past messages and signatures can no longer be trusted, regardless of the revocation date. That's why when you revoke a key on github, all your previous commits' signatures turn red.
I've never understood why no one's succeeded in doing anything about this after all these years.
Furthermore metadata transparency can be made less problematic by using email aliases.
now what's interesting here is a potential future development of deltachat where SMTP is only used to negotiate the peer to peer connection, and the actual chat messages are sent over the direct connection. although it sounds kind of weird to build a chat solution on top of SMTP and then bypass SMTP in the end.
the remaining benefit would be the ability to talk to people who don't use deltachat. not needing another account on a new service. not needing to develop or maintain server infrastructure.
wait, in a way it's already there: https://github.com/ArcaneCircle/live-chat
now adapt that to storing messages... ;-)