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> For example, in the classic case when a user adds a new device and wants history to be available on both you can't let the devices controlled by one person si
by k1t 6y ago
> For example, in the classic case when a user adds a new device and wants history to be available on both you can't let the devices controlled by one person simply sync with one another.
> To do so would be making a security concession to the other members of the chat in that they no longer verify every destination of their message.
You can't "verify every destination" with Signal anyway. Maybe the message is going to my phone, maybe it's going to my phone and my desktop - the sender can't tell.
Sure, if you are trying to add an entirely new recipient to a conversation, then of course you can't send them the entire conversation history - but nobody is asking for that.
What people want is the ability to add a new device for an existing recipient, and have the history sync across.
With Signal I can already add a new device and continue existing conversations without the other participants being notified that I've added a new device. Adding conversation history doesn't diminish anything from a security perspective.
- gshulegaard 6y agoAre you sure about this? > With Signal I can already add a new device and continue existing conversations without the other participants being notified that I've added a new device. Just today I had a group chat notification that said: "More than one member of this group is no longer marked as verified. Tap for options" Tapping brought me to a menu that said: "Safety Number Changes -- The following people many have reinstalled or changed devices. Verify your safety number with them to ensure privacy" At which point I was given the option to re-verify (e.g. via a provided QR code), but also the option to manually mark "verified". That is to say something does notify participants of changes to recipient devices.
- smichel17 6y agoSignal still had a single primary device, your phone. What you describe happens when someone installs Signal on a new phone (or reinstalls on the current one). Linked devices are different. There is no notification when someone adds a new linked device. That's because the only way to add a linked device is to scan a QR code on the device with your phone, then confirm you want to add the device. The device is implicitly trusted, because only a trusted device can add it. (It is also possible to trigger the re-verification from the desktop manually by clicking "reset secure season" in the conversation menu, but that's separate from adding a device.) Aside: Implicit trust like this is a great trade-off, because otherwise you'd have to verify each of their devices from each of your devices, which means approximately nobody will ever do it. Ask anybody who used Matrix/Element E2EE prior to a couple months ago ;D.