> It's done to help their user acquisition. It uploads your contacts to match against other contact lists and let you know who's on Signal. I may be wrong, but

> It's done to help their user acquisition. It uploads your contacts to match against other contact lists and let you know who's on Signal. I may be wrong, but I think this functionality existed prior to the server-side state effort. I recall when people in my contact list joined Signal, I was notified. However, these days I do not keep contacts in the phone contact list. It's too big and juicy a target. > And besides, a 4-6 digit PIN would be a terribly insecure way to "encrypt" anything server-side :) Very much so. That does seem odd.