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It's not optional because you don't know whether the people you are communicating with have it enabled. One person in a group chat with the feature enabled undo

It's not optional because you don't know whether the people you are communicating with have it enabled. One person in a group chat with the feature enabled undoes the forward secrecy for everyone in the group chat. A cloud backup eliminates any forward secrecy. It used to be that in Signal, when you have a message on your device and it is deleted (or a disappearing message disappears), then it is truly gone and can never be recovered. Now with backups, since the key that was used to encrypt it to the cloud remains on your device, it can be recovered even after the message is deleted or disappears. The only way to "truly" opt-out is to, as you say, set a disappearing message timer for <24 hours.

uv-depression 1y ago
Yeah, and all of that's already true right now because messages are stored on those users' devices already. You'll be heartbroken to hear that those users can also take a screenshot of your disappearing messages and send it to anyone. There are fundamental limitations to what a messaging app can protect you from.
- fragmede 1y ago
  While the analog hole will always exist, and you can't make it actually impossible, Snapchat's quite good at that screenshot thing. Both platforms have APIs to prevent, or at least notify on the use of screenshot. It's weird that signal doesn't use any of them.
  - throawayonthe 1y ago
    i know of ~3 currently working methods to take screenshots on snapchat it isn't "weird that signal doesn't use any of them" because it does [1] use both, just not for giving a false sense of security to your correspondents [1] https://support.signal.org/hc/en-us/articles/360043469312-Screen-Security https://support.signal.org/hc/en-us/articles/360043469312-Sc...
    - fragmede 1y ago
      What are they, other than the analog hole? Screen security so that I can't see the app on my phone in preview during app switching isn't the same thing as stopping screenshots.
      - throawayonthe 1y ago
        android emulator (i think bluestacks still works), web snapchat client + BetterSnap extension (you can even save the original media file!), on graphene it seems to detect screenshots but not video recording (likely not intentional, there was an open issue to block screenshot detection but no devs were interested iirc) it's a lost cause except maaaybe provisioning drm keys but even then, as you say, analog hole re: screen security isn't the same thing - that's what i mean, signal does use those very APIs but not for a half-assed snitching feature
        fragmede 1y ago
        Oh interesting. Yeah, I mean, iOS has the API so it seems silly that they don't do anything about it there, but I guess if you support a diverse userbase like they have to, then user education is impossible and a false sense of security would be a bad thing to give to uaers
pluto_modadic 1y ago
this is the same argument as saying "you shouldn't have remote delete requests". Yes, people can screenshot or export. That doesn't mean you shouldn't have a nicety that generally works pre-compromise or pre-evil. Locks just keep honest people honest.

uv-depression 1y ago

Yeah, and all of that's already true right now because messages are stored on those users' devices already. You'll be heartbroken to hear that those users can also take a screenshot of your disappearing messages and send it to anyone. There are fundamental limitations to what a messaging app can protect you from.

fragmede 1y ago
While the analog hole will always exist, and you can't make it actually impossible, Snapchat's quite good at that screenshot thing. Both platforms have APIs to prevent, or at least notify on the use of screenshot. It's weird that signal doesn't use any of them.
- throawayonthe 1y ago
  i know of ~3 currently working methods to take screenshots on snapchat it isn't "weird that signal doesn't use any of them" because it does [1] use both, just not for giving a false sense of security to your correspondents [1] https://support.signal.org/hc/en-us/articles/360043469312-Screen-Security https://support.signal.org/hc/en-us/articles/360043469312-Sc...
  - fragmede 1y ago
    What are they, other than the analog hole? Screen security so that I can't see the app on my phone in preview during app switching isn't the same thing as stopping screenshots.
    - throawayonthe 1y ago
      android emulator (i think bluestacks still works), web snapchat client + BetterSnap extension (you can even save the original media file!), on graphene it seems to detect screenshots but not video recording (likely not intentional, there was an open issue to block screenshot detection but no devs were interested iirc) it's a lost cause except maaaybe provisioning drm keys but even then, as you say, analog hole re: screen security isn't the same thing - that's what i mean, signal does use those very APIs but not for a half-assed snitching feature
      - fragmede 1y ago
        Oh interesting. Yeah, I mean, iOS has the API so it seems silly that they don't do anything about it there, but I guess if you support a diverse userbase like they have to, then user education is impossible and a false sense of security would be a bad thing to give to uaers

pluto_modadic 1y ago

this is the same argument as saying "you shouldn't have remote delete requests". Yes, people can screenshot or export. That doesn't mean you shouldn't have a nicety that generally works pre-compromise or pre-evil. Locks just keep honest people honest.