Re: [Txauth] RS/AS communication for multiparty cases

[Denis <[e-mail]>]

Hello Fabien,

In 2017, I made a presentation at the OAuth workshop in Zurich.

The paper is available from: 
https://zisc.ethz.ch/wp-content/uploads/2017/02/pinkas_privacy-by-design-eID-scheme-supporting-Attribute-based-Access-Control.pdf

The slides are available from: 
https://zisc.ethz.ch/wp-content/uploads/2017/02/pinkas_privacybydesign.ppt
_Note_: The slides should be viewed "full screen" to get the animations.

The general approach is how to construct from scratch a "privacy by 
design" architecture taking also into consideration "security by design".

Coming back to your requirement, I would not cover it if it infringes 
the sentence "the RS and the AS never communicate directly".

You should start your design by defining the trust relationships, then 
apply the privacy requirements while not forgetting the security 
requirements.

Denis

> Hello Denis,
>
> I have been following your comments. I still fail to see the global 
> privacy preserving architecture you're proposing. It would help to get 
> a more thorough proposal if you can.
>
> But more specifically, I have a comment on :
>
> "I would have preferred that you meant: the RS and the AS never
> communicate directly, which is indeed a nice property to follow
> to ensure the user's privacy."
> I think that may come as an issue in some cases, especially for multiparty patterns (like in UMA). Typically we may wish the RS to start a grant request and use the handle to continue until a token is generated.
> I think those cases, which weren't initially covered by OAuth2, are very important to cover as well. How would you cover such requirements?
> Fabien
>