Mastodon desperately needs end-to-end encryption for DMs. It's going to be ugly when Mastodon servers start getting hacked
I haven't read too much about Mastodon/ActivityPub yet, but I'm guessing server admins can impersonate anybody on their server and change the text of anyone's posts (toots?). That could also be fixed once the key distribution infrastructure is in place for e2e encryption.
New User Question: How can I trust any given server?

As best I can tell, the operator of a server has complete control of my account, and could do things like leak my password and email, falsify or...

reddit
@willc Oof. Frustrating to see so many answers there that I disagree with. E.g. "Mastodon Admin here. We can't see or leak your password." is clearly wrong or at least misleading. Hopefully that will shift now that infosec folks are here :)
@timmclean How can Mastodon admins see your password?
@willc they can log it when you sign in or register
@timmclean I’d love to see a proof of concept for that.
@willc Log out. Go to the Sign In page. Open the Network tab of dev tools. Sign in. Look at the HTTPS request sent to the server. It contains your password. The server is controlled by the server admin on a domain owned by the server admin using a TLS cert set up by the server admin, so it can log any request it receives. That's just how the web works!

@timmclean “That’s just how the web works.”

👀