Earlier quoted context omitted.
The point of E2E is only to make sure that Alice is talking to Bob and nobody else can pretend to be either of them or eavesdrop. There is no reason whatsoever to include where else the message may be sent, encrypted or not. Consider E2E protected email service. You send me the final designs over this encrypted channel. Then I put the designs onto a USB drive and give them to my printer to print. Then I hang them as…
>You are confusing Snapchat mechanics for encryption. I think we're talking about this from two different perspectives. You're considering a user in someone's conversation with a modified, archiving client. Yes, you obviously can't prevent that from a technical side, and it doesn't break Signal's E2E. It would be even simpler to do this with the unmodified Android Signal client, which essentially allows message expor…
If you want to make sure nothing is ever archived, there is no software-only solution. If you control the hardware, in theory you can mandate that everything from the OS level-up is a reproducible build and you know for a fact that the messaging client does not allow any export feature. But also, you still have the problem of someone taking a picture of the screen. The real way to do this would be to control the software, hardware, and environment, aka a SCIF. If you want me to see classified war plans, confiscate all my electronics then show me what I need to see in a controlled environment where I can’t make copies. Messaging apps just simply can’t do any of that.