> Better security here doesn't seem hard to implement.
You seem to assume it would be very simple to implement this — how do you come to this conclusion? My priors would suggest that the vast amount of effort that went into the Signal protocol renders low-hanging fruit regarding privacy fairly unlikely.
The GP is actually right here, Signal keeps the call log in the message history (deleting the call entry from the message history deletes it from the call log), but the disappearing messages setting doesn't get applied to the call log.
It's weird to see a bunch of messages, a call, more messages, and a day later the messages around are gone, but the call remains in the history. They could have just applied the disappearing messages settings to the call entries too, as it would be natural to do, and this problem wouldn't exist.
I don't think it's malicious, because what the server knows is independent of what the UI shows, but it's a very odd UI issue that does reduce privacy.
They keep it in the UI, therefore I assume in the database as well. If you delete a call entry in the message history (like you delete a message), it gets removed from the "call history" tab as well.
> vast amount of effort that went into the Signal protocol
If it requires protocol development, I'd agree. I expect - knowing no more than Signal's blog posts - that it has two components:
* Local database: These records need a retention period column, somehow - however they implement it with text messages. That seems straightforward.
* 'Distributed retention' - implementing the retention period setting on the remote devices of other call participants. I expect they would do it the same way they do with text messages, and I would guess it's just a field in a packet somewhere; e.g., establish a secure connection and then in the call's initial packet,
You seem to assume it would be very simple to implement this — how do you come to this conclusion? My priors would suggest that the vast amount of effort that went into the Signal protocol renders low-hanging fruit regarding privacy fairly unlikely.