Does telegram really delete messages in secret chats?

Question

Information Security

1. Telegram itself states that messages in secret chats are deleted completely. Is it true?
   
2. If in regular chats both interlocutors have deleted their correspondence, is it deleted permanently?
   
3. If a user deletes his message in group chats, is it permanently deleted?
   
4. If an admin deletes a post in a channel, is it permanently deleted?
   

Or is everything deleted deleted only for the user, but is actually stored on the servers forever?

Answer 1

Telegram claims that messages are being deleted. But is it really so? This we will never know. Most likely, yes, they are deleted, but if the telegram wants, it can save them.

Answer 2

Let's start with the fact that nothing can be stored forever on servers, to free up "space", some data is deleted.
Well, to answer your question, I advise you to read the "Terms of Use" of Telegram.

Answer 3

comrade major, and the last question: where is bench61 ?

Answer 4

1. yes, in secret chats you can set up self-destruction of messages.
2. In a secret chat, messages are stored only by the chat interlocutors. it is stated that the messages in it are sent directly from the interlocutor to the interlocutor, bypassing the cart server, i.e. p2p exchange.
plus the channel encryption keys exist only for the interlocutors of the secret chat. any intermediate node intercepting at least the entire data stream will not be able to decrypt it. the functions of sending the key to the server were not found in the client.
3.4. it seems yes, a technical signal is sent to delete such and such a message.
so download the source code of the cart client, disable the deletion of messages in them and compile, the modified client has no problems.
or write a logger bot to sniff all messages or come up with something else, the possibilities are millions.

Answer 5

Yes, at the touch of a button, everything is deleted, the disk is formatted with triple overwriting, those who read it are eliminated and the room is disinfected.
It is impossible to answer your questions directly, but it is safe to say that:
1. It is impossible to control the behavior of the client application from the server. It is always possible to modify the client in such a way that a complete archive of all messages is stored forever.
2. Whether deleted messages are deleted from the server, only developers / server administrators know, and not the fact that they know correctly. The situation when developers think that they are deleting information, but in fact they are not, and it is only marked as deleted at one or another storage level, is more than common. It is very unlikely that messages are reliably deleted immediately on the server side, this is very resource intensive.
3. Secret chats use end-to-end encryption. Assuming that a third party did not interfere with the key exchange on the side of the telegram servers (which you have to believe or control over an independent communication channel), storing such messages on the server does not make it possible to decrypt them on the server side.

Answer 6

Only those who have access to the source codes of the cart server can accurately answer all these questions, everything else is at the level of conjecture. The cart may claim that it deletes everything, but there is no way to verify this without having access to its infrastructure.
Therefore, the answer here is only this - either you take their word for it that they delete everything - or you don’t use it. All this chatter about end-to-end encryption is for lamers. It's not hard to write a client with a modification that will merge the current encryption key where they need it. (Here they can be anyone - Durov, NSA, FSB ...)
That is, almost like with the spectrum - there is a possibility, but the operation is difficult. The operation is difficult, but when the mission is critical, then you should not discount it.