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Comment by gefhfffh | Hacker News Reader

I have nowhere called them end-to-end encrypted Backups, that's a straw man.

> Regarding the security theater, the backups encrypted with your password are far more vulnerable to being compromised than any of the popular e2e encryption protocols.

How, so? Are you aiming weak passwords? (One is provided for you ("security key"), however you can opt into a custom one that is not directly used for encryption ("security passphrase"))? Or are you referring to PFS, which isn't a property of all popular e2e protocols either, and "far" would be quite a stretch.

How does all that disprove that Element uses true e2ee?

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It is proven beyond doubt that whatever Element fetches from their own servers and decodes on application launch are not messages encrypted using e2ee protocols. It is also completely clear that it does reduce the privacy of user messages. I don't know what else to argue about here.

Element does not fetch any message from their servers in general. If you use a server hosted by Element and don't disable encryption, e2ee encrypted messages will be fetched from their servers.

What is "it" that in your opinion should reduce the users privacy?

> I don't know what else to argue about here.

I don't know what you are arguing about right now. What I know, is that I have disproven your original thesis (visible messages right after login through a password is not possible with e2ee) by explaining how it works and providing an example that has put that concept into practice.

If you feel there is anything to discuss, or if you have any further questions, don't hesitate to respond though.

I'll add link that adds technical Implementation details, in case you are interested: https://matrix.org/docs/guides/implementing-more-advanced-e-...

Maybe what people like to know is how Matrix's backup encryption is different from WhatsApp encrypted backups:

https://www.whatsapp.com/security/WhatsApp_Security_Encrypte...

Thanks for the link. Actually, didn't even know that WhatsApp changed their backup mechanism, which previously used a mechanism that allowed e.g. google to obtain the messages.

Overall, the concept seems to be the same: use a secret, only known to the client to secure data stored at a untrusted location.

The major differences include:

- closed vs open source (it's easy to validate the mechanism in the implementation whereas you pretty much need to trust WhatsApp that they don't leak the key)

- WhatsApp uses a third party provider for storing the data whereas with Matrix your Homeserver is responsible for messaging and the backup

- only the main app can access the backup whereas with Matrix any of your clients can independently read and write to the backup (because there is no main client)

- WhatsApp stores everything in the backup, a Matrix client only the keys, because the messages are stored somewhere else

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