Re: [PATCH 11/21] doc: PKEX support for DPP

[Denis Kenzior <denkenz@gmail.com>]

Hi James,

> 
> I guess my question is really how you communicate this to the enrollee.
> 
> The use case for a human user really comes down to not wanting to type in a 64 
> character hex string :) So auto-generating a complex code doesn't make much 
> sense in this regard.

Who said anything about a 64 character hex?  I'm thinking more about a 10-12 
character complex password like you see the web browser generate.  However, I'm 
pretty sure we need the ability to generate the code every time:

"If both sides have a user interface, this technique can be used to bootstrap 
trust by exchanging bootstrapping information including the bootstrapping keys 
that are to be used for a DPP exchange requiring mutual authentication. This 
bootstrapping technique shall use a fresh code each time and the same code shall 
not be used with different Peers."

Correct me if I'm wrong, but PKEX is no different than regular DPP.  It simply 
uses a code instead of a QR code for establishing the initial trust channel 
(giving high degree of confidence to both parties that the exchanged public keys 
are trusted).  The more complex the code, the better the chance that the code 
can be trusted (i.e. it wasn't guessed).  It still inherits the same basic 
attributes, roles, etc.


> 
> For a headless device auto-generation just won't work since the password is 
> baked into the image. I considered generating a single bootstrapping key and 

Doesn't this run counter to what PKEX is about?

> bake that into the image (no PKEX) but I question the possibility of offline 

With a strong password, probably eons, unless quantum computing is involved.

> attacks. With PKEX the bootstrapping keys are changed upon each protocol run so 

But you're still sharing a PSK in the end?  Why go through all this trouble?

> I think there is forward secrecy there. Plus PKEX uses mutual authentication to 

WPA3 has forward secrecy as well.  So what are you trying to achieve?

> prevent someone from coming in and configuring the new devices who shouldn't be.
> 

The gold standard is still WPA-Enterprise with EAP-TLS.

Regards,
-Denis