“Telegram is not a private messenger. There’s nothing private about it. It’s the opposite. It’s a cloud messenger where every message you’ve ever sent or received is in plain text in a database that Telegram the organization controls and has access to it”
“It’s like a Russian oligarch starting an unencrypted version of WhatsApp, a pixel for pixel clone of WhatsApp. That should be kind of a difficult brand to operate. Somehow, they’ve done a really amazing job of convincing the whole world that this is an encrypted messaging app and that the founder is some kind of Russian dissident, even though he goes there once a month, the whole team lives in Russia, and their families are there.”
" What happened in France is they just chose not to respond to the subpoena. So that’s in violation of the law. And, he gets arrested in France, right? And everyone’s like, oh, France. But I think the key point is they have the data, like they can respond to the subpoenas where as Signal, for instance, doesn’t have access to the data and couldn’t respond to that same request. To me it’s very obvious that Russia would’ve had a much less polite version of that conversation with Pavel Durov and the telegram team before this moment"
With my limited knowledge of cryptography, this is how I understand it:
The distinction to make is that the user’s password is not the encryption key - it only gives access to the key. So even if the user has the same password on a new device, there would be no way to decrypt the data without the original key.
In order to maintain full privacy, data has to be encrypted on device before sending it through any server (whether to another participant in a chat, or for backup). This means that the encryption key has to be on device.
If that key was copied over to a location not controlled by the user (e.g. Telegram server), then that location would have access to the key and can decrypt any data encrypted by that key. In the same vein, if a user loses their phone then that encryption key must be lost, so encrypted data cannot be decrypted on a new phone.
Which means that the only way that Telegram can provide the chats on a new phone (when the user has no access to the old phone) is if they have access to the encryption key and can provide it to the new phone.
From my experience with that: Telegram restored all unecrypted chats when I swapped phones without asking me for any passwort / key. I literally just confirmed my phone number and all my chats / groups / contacts appeared.