[Nikker]

Is this a different implementation of Diffie–Hellman? As far as I can tell (and I am likely wrong) there needs to be one successful connection attempt using a secure protocol, in this case HSTS, to detect if the redirect was indeed to the correct site or a MitM attack.

[azdle]

HSTS isn't a protocol, it bascailly a flag that tells a browser to only use TLS to connect to a specfic domain. It normally does require one successful connection for the server to tell it, but both chrome [0] and firefox [1] have a list of sites built-in so that even the first time they connect they'd be TLS.

[0] https://src.chromium.org/viewvc/chrome/trunk/src/net/http/tr...

[1] https://blog.mozilla.org/security/2012/11/01/preloading-hsts...