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Comment by ilogik | Hacker News Reader

If you don't trust the person that wrote the software, it doesn't matter if it's E2E encrypted or not. There could be a back-door

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If you don’t trust a communication channel, you could always do a Diffie-Hellman key exchange in the clients which lets you create a shared encrypted channel between two parties by sharing public keys. This works even if they are trying to monitor you.

Doesn't work with simplex channels.

It can work with simplex channels if you have the public key of the receiver. Both parties just need to know each other's public keys to create encrypted communication. After exchanging the public keys, it can be one-way communication.

I guess it wouldn't work for a one-to-many channel though, just individual one-to-one channels.

which software ? You might have 3rd party client implementation that talks with another client and only server would be "unknown" party.

E2E allows both clients to talk to eachother without server having a way to snoop on

E2E encryption happens on the client side, not on the server side. Therefore, no need to trust anybody, as long as the software is open-source.

If you run binaries compiled by the author of the software it wouldn't matter that it is open source, so play store is out of the question. So then it must be open source and you must use distributor you trust: your distro maintainers and F-Droid.

Also you must trust that people did really take a look at the code.

That's exactly how Signal and Keybase work, and nobody has any problems with that.

I had exactly this in mind. Mostly if I wouldn't trust the author with binaries I wouldn't really trust with source code either.

That’s because most people hear “E2E” and think that somehow means they can automatically trust the client app. It’s a panacea.

> Therefore, no need to trust anybody, as long as the software is open-source.

Demonstrably untrue. You must trust that the contributors are trustworthy, they have implemented a strong security posture for their project, and that the code is reviewed by people who are trustworthy. Many open-source projects have been, and continue to be, compromised on a regular basis.

> You must trust that the contributors are trustworthy

In theory, that's only the case if you are unable to review the code yourself.

In practice, it's like saying that TLS encryption is pointless, because one needs to trust every single person who implements it.

We're sure you review all the code you run.

That's only the case if I am unable to review the code myself, before any update, I fully understand the code, and I am smart enough that the contributors are unable to pull a fast one on me.

Given that I'm not a cryptography expert, I have a limited number of hours in the day, and open-source supply chain attacks are typically obfuscated, I don't consider that to be a trivial statement.

Not on phones.

You have 0 guarantee that the open source code is actually the code that runs on your device. And you have 0 guarantee that the device itself is not compromised. And you have 0 guarantee that the OS is not storing your data.

E2E on mobile devices is a security blanket with holes the size of the solar system.

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