My biggest annoyance with Signal is that getting a new phone ends up wiping out all conversation history with apparently no way to transfer it.
This loss of user data is not advertised well enough up front, and leaves users feeling tricked. In many contexts loss of user data is an even bigger sin than weak security.
What's ironic here is that in the adversarial setting the application is designed for, unexpected retention of user data (on end-user devices) is a sin.
I like to think about messages being ephemeral. If a piece of information needs to be saved, I just store it outside the messaging app. This includes media files, too.
That’s fine. But Signal should then advertise itself as unsuitable for general-purpose communication, primarily relevant when someone is specifically worried about adversaries reading the communication.
I can see how this makes sense for journalists, dissidents, diplomats, criminals, corporate executives, etc., but if data is under threat of disappearance, regular people should be warned away and told to use something else for day-to-day communication.
Personally, I'm happy to lose the data. I found it odd that with both phones and the SIM on the desk in front of me, I couldn't figure out how/if I could vouch for my key changing in any way.
Needing to say I have a new phone just trust me largely defeats the purpose.
If you are on an Android device you can export an encrypted backup and scan a QR code / type in the password to the encrypted archive to transfer messages / group memberships with only a safety number change in most cases.
I think that's the opposite of what I want? I want to inform people of the new safety number using the old channel and purge all data like a good user.
In this respect a keybase like model makes more sense to me.
Two small corrections: Signal-Android's backup works with a passphrase only (no QR codes involved) and does not cause safety number changes on restore.
This loss of user data is not advertised well enough up front, and leaves users feeling tricked. In many contexts loss of user data is an even bigger sin than weak security.