Matthew Toseland wrote:
> You're talking about geeks. And even they don't usually go to the effort. But 
> this whole conversation kicked off when you said files were inconvenient. :)

They are inconvenient - if I could convince the rest of the world to use
short refs, I would. But not passwords, that would be a step backwards. ;-)

> I still don't see how you are going to use them. Bob makes up a password and 
> gives it to Alice out of band over the phone. Alice proves she has the 
> password through a challenge/response. Alice gets 3 tries. What's the attack 
> vector?

Sorry, I misunderstood. I thought you were proposing that there should
be no up-front exchange of pubkeys/passwords, but after establishing the
connection it should be checked for MITM attacks by generating a
password from the JFK pubkeys and verifying it OOB (like Zfone does).
But you weren't, so forget I mentioned it and substitute my usual
objection to an up-front exchange of passwords: the users won't use a
secure channel, tampering with channels is harder than observing them,
so pubkeys are preferable to passwords.

> Impossible without two way exchange of very long lines of text, with at least 
> one way untamperable. Which is not remotely realistic, except in the trivial 
> case of sending an encrypted email.

35 characters of base32 (IP + port + 128-bit pubkey hash) is not
remotely realistic? It's only four phone numbers! :-)

Cheers,
Michael

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