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Signal recently added 'disappearing messages' which lets you specify how long a chat you initiate remains before being deleted.

noasaservice 5y ago
And a screenshot, or another camera, or a rooted phone can easily defeat that. The analog hole ALWAYS exists. Pretending it doesnt is ridiculous.
- wizzwizz4 5y ago
  > And a screenshot, or another camera, or a rooted phone can easily defeat that. Not if the message has already been deleted. Auto-deleting messages are so the recipient doesn't have to delete them manually, not so the recipient can't possibly keep a copy.
  - summm 5y ago
    Exactly this. Even more: Auto-deleting messages are also that the sender doesn't have to delete them manually. Most people do not understand this. I even had a discussion with an open source chat app implementer who insisted on not implementing disappearing messages because they couldn't be really enforced.
- deleted 5y ago
  [deleted]
- timbit42 5y ago
  What made you think I was pretending it doesn't?
- hiq 5y ago
  That's a different threat model, no messaging app is trying to protect the sender from the receiver. Disappearing messages are meant to protect two parties communicating with each other against a 3rd party who would eventually gain access to the device and its data.
- bigiain 5y ago
  Wickr has a "screenshot notification to sender" feature (which of course, can be worked around by taking a pic of the screen without Wickr knowing you've done it).
bigiain 5y ago
Not "recently". Disappearing messages have been there for at least 5 or 5 years. Almost _all_ my Signal chats are on 1 week or 1 day disappearing settings. It helps to remind everyone to grab useful info out of the chat (for example, stick dinner plan times/dates/locations into a calendar) rather than hoping everybody on the chat remembers to delete messages intended to be ephemeral. The "$person set disappearing messages to 5 minutes" has become shorthand for "juicy tidbit that's not to be repeated" amongst quite a few of my circl3es of friends. Even in face to face discussion, someone will occasionally say something like "bigiain has set disappearing messages to five minutes" as a joke/gag way of saying what used to be expressed as "Don't tell anyone, but..." (I just looked it up, https://signal.org/blog/disappearing-messages/ https://signal.org/blog/disappearing-messages/ from Oct 2016.)
- timbit42 5y ago
  Maybe it was only added recently on the desktop client.
upofadown 5y ago
Keep in mind that any time a message is on flash storage there might be a hidden copy kept for flash technical reasons. It is hard to get to (particularly if the disk is encrypted) but might still be accessible in some cases. I think encrypted messengers should have a "completely off the record" mode that can easily be switched on and off. Such a mode would guarantee that your messages are never stored anywhere that might become permanent. When you switch it off then everything is wiped from memory. That might be a good time to ensure any keys associated with a forward secrecy scheme are wiped as well.

noasaservice 5y ago

And a screenshot, or another camera, or a rooted phone can easily defeat that. The analog hole ALWAYS exists. Pretending it doesnt is ridiculous.

wizzwizz4 5y ago
> And a screenshot, or another camera, or a rooted phone can easily defeat that. Not if the message has already been deleted. Auto-deleting messages are so the recipient doesn't have to delete them manually, not so the recipient can't possibly keep a copy.
- summm 5y ago
  Exactly this. Even more: Auto-deleting messages are also that the sender doesn't have to delete them manually. Most people do not understand this. I even had a discussion with an open source chat app implementer who insisted on not implementing disappearing messages because they couldn't be really enforced.
deleted 5y ago
[deleted]
timbit42 5y ago
What made you think I was pretending it doesn't?
hiq 5y ago
That's a different threat model, no messaging app is trying to protect the sender from the receiver. Disappearing messages are meant to protect two parties communicating with each other against a 3rd party who would eventually gain access to the device and its data.
bigiain 5y ago
Wickr has a "screenshot notification to sender" feature (which of course, can be worked around by taking a pic of the screen without Wickr knowing you've done it).

bigiain 5y ago

Not "recently". Disappearing messages have been there for at least 5 or 5 years. Almost _all_ my Signal chats are on 1 week or 1 day disappearing settings. It helps to remind everyone to grab useful info out of the chat (for example, stick dinner plan times/dates/locations into a calendar) rather than hoping everybody on the chat remembers to delete messages intended to be ephemeral. The "$person set disappearing messages to 5 minutes" has become shorthand for "juicy tidbit that's not to be repeated" amongst quite a few of my circl3es of friends. Even in face to face discussion, someone will occasionally say something like "bigiain has set disappearing messages to five minutes" as a joke/gag way of saying what used to be expressed as "Don't tell anyone, but..." (I just looked it up, https://signal.org/blog/disappearing-messages/ https://signal.org/blog/disappearing-messages/ from Oct 2016.)

timbit42 5y ago
Maybe it was only added recently on the desktop client.

upofadown 5y ago

Keep in mind that any time a message is on flash storage there might be a hidden copy kept for flash technical reasons. It is hard to get to (particularly if the disk is encrypted) but might still be accessible in some cases. I think encrypted messengers should have a "completely off the record" mode that can easily be switched on and off. Such a mode would guarantee that your messages are never stored anywhere that might become permanent. When you switch it off then everything is wiped from memory. That might be a good time to ensure any keys associated with a forward secrecy scheme are wiped as well.