>I strongly disagree. A lot of critical work has been done with email + PGP, and that's about as leaky (in terms of metadata) as it gets. Obviously there are use cases where you do worry about this, but "storing data on the Internet" is not as such always a problem for those who need the highest security guarantees. Signal adopting alternative user identifiers would open it to use in some of these extreme cases, but would not (of course) make it usable in every situation - and that's okay.

I'm old school. If it's connected to the Internet, eventually it will be compromised.

Yes, strong encryption can (and does) make data compromise immensely more difficult in terms of time and resources (much longer than our star will exist -- about five billion years -- which isn't really that big a deal, since the Earth will be uninhabitable in a billion years or so), but once that centralized server(s) is compromised, all bets are off.

I don't disagree that strong encryption is a valuable tool for maintaining data privacy and integrity, but it absolutely does not reduce the risk to zero.