Comment by skrebbel

I'm a complete crypto noob, but if i do

   keybase encrypt maria -m 'Grab a pint tonight?'

(from their front page) and Keybase.io (or my connection) happens to be compromised, won't it be possible for compromised-Keybase to send me the wrong public key for username "maria", thus allowing others to read my message?

I guess the same could be said about someone posting their GPG key on an unencrypted mail or usenet post, though, so maybe the problem is mostly hypothetical.