[jfr]

Wrong.

The OpenSSH model implies that you check the fingerprint of the public key before you send encrypted data using that key. That is why SSH shows you the fingerprint of the server key when you first connect, and you have to answer "yes" in order to accept the key and add it to your keyring. You are supposed to have talked to the person managing the system and that person should have given you the fingerprint of the key.

It is virtually impossible for the ISP to intercept and sniff the stream without changing the fingerprint.

The user still has to trust its SSH client.

[tptacek]

"Wrong! Random people will totally verify key fingerprints when they're logging into Google Mail at Starbucks! After all, that's what every sysadmin does with SSH, right!"

[jfr]

gmaslov is clearly talking about the OpenSSH trust model. You are confusing it with the Trust On First Use model, which is not the same thing.

[tptacek]

I have no idea what you are trying to express here. "Trust On First Use" is a synonym for key continuity. The fact that you have to type "yes" when SSH does it and click a series of buttons when a browser does it doesn't change anything.

I think you think that "Trust On First Use" means "automatically accept keys the first time you hit a site". In fact, that's only true in practice. Presumably everyone's going to get the "Watch Out! This Could Be Iran!" dialog from their browser, too.

[vladd]

There isn't any non-Internet communication channel that users could use to find Google's fingerprint. Google won't give their fingerprints on the phone for billions of web users.

Theoretical models that have no practicality in a given real life context aren't worth discussing as a solution.