Re: [Cfrg] [CFRG] PAKE / Hash2Curve First Internet draft for balanced CPace subcomponent available

[Björn Haase <[e-mail]>]

Dear Feng,

 >I can’t talk about other people’s reasoning...

and also I'm not able to or interrested in reading other people's minds.
I did not mean to be offensive. I aim at being fair to all candidates in
the discussions and specifically also to J-PAKE.

I agree with you that reasoning what other peoples did think is
guesswork. Maybe let's better re-phrase my earlier statement more
accurately as follows:

J-PAKE beside the two additional rounds and the efficiency
disadvantages, in my opinion has four outstanding points:

1.) The simple structure that avoids the risk to overlook errors and
problems in the proof strategy (as pointed out correctly by Scott!)
because with your construction, you don't need assumptions similar or
close to things such as the "known-exponent assumption". You simply
proove that the remote side did now the exponent and use this in the proof.

2.)  with this structure, you don't need programmable RO

3.)  you don't need the complexity of hashing to curves.

4.) and finally:  It's not covered by the patents.

Even if it was quite obviously not your main objective, I believe that
from all of the advantages the feature 4.) might indeed have been the
single one most valuable property of J-PAKE for industry.

Yours,

Björn.

P.S.:

FYI: With our company we have actually tried to get / evaluate the cost
of licences. That did turn out to be extremely painful (already to find
the right contact person, agree on commonly accepted NDA forms, agree on
licensing contract frameworks, trying to setup the reporting process
regarding production and number of uses of the patent, volumes in the
specific countries with valid patent and without, what to do with apps
and service software tools that are typically shipped for free, where
royalty conditions of the patent holder might force you to *sell*
individual licenses or require complex online registering processes for
your own customers, such that you could report how many times the
software is actually installed and used and in which country ....

In the end, our legal department requested us to implement a solution
not covered by patents ...