Re: [Privacy-pass] Private Access Tokens and Privacy Pass Architecture

[Alex Davidson <[e-mail]>]

Hi,

Broadly speaking, I think the reorganisation of the protocol, architecture,
HTTP auth docs make sense. Having not followed the work on Private Access
Tokens very closely, I think it would be beneficial to have a presentation
on this topic to the WG. Specifically, it would be useful to hear more
related to the motivation and intended goals of this draft, and the
applicability of this work to the WG.

I also found a few minor issues after doing an initial read-through of the
docs:

- Section 3 of the HTTP auth doc seems to already be covered in Section 3.2
of the architecture doc, maybe this could be replaced with a simple
citation?
- This may be a hangover from a previous iteration, but in Section 4.2 of
the architecture doc the advised key rotation period (1-12 weeks) is not
consistent with the table in Section 6 (2-24 weeks).

I will read the linked drafts over the next few days more thoroughly and
post any additional things that I notice here.

Cheers,
Alex

On Thu, Dec 16, 2021 at 4:41 PM Steven Valdez <svaldez=
[e-mail]> wrote:

> Following up on IETF 112, and discussions about Private Access Tokens (
> https://www.ietf.org/archive/id/draft-private-access-tokens-00.html) in
> SECDISPATCH to move it to PRIVACYPASS, the authors have been working on a
> proposed re-architecture of the PRIVACYPASS documents to support both the
> existing privately verifiable construction (based on VOPRFs), as well as
> the publicly verifiable construction (based on RSA Blind Signatures) and
> the Private Access Tokens design.
>
> Links and a discussion to the proposed drafts are below. Please review
> them and provide feedback!
>
> Due to the scope of the changes, it might be useful to go over these
> drafts in a meeting. Chairs, would it be possible to get an interim
> scheduled in January to discuss these changes?
>
> ---
>
> Current proposed drafts of the documents are:
>
> Architecture:
> https://ietf-wg-privacypass.github.io/base-drafts/caw/arch-refactor/draft-ietf-privacypass-architecture.html
> HTTP Auth Scheme:
> https://tfpauly.github.io/privacy-proxy/draft-pauly-privacypass-auth-scheme.html
> PrivacyPass Issuance Protocol:
> https://ietf-wg-privacypass.github.io/base-drafts/caw/pp-issuance/draft-ietf-privacypass-protocol.html
> Rate-limited Token Issuance Protocol (Private Access Tokens):
> https://tfpauly.github.io/privacy-proxy/draft-privacypass-rate-limit-tokens.html
>
> The Architecture document provides the shared architecture that different
> tokens build on top of, generalizing the existing architecture of Issuer,
> Client, Origin to include an Attester (which is currently implicit in the
> existing architecture). It defines the purpose and requirements for Privacy
> pass issuance and redemption.
>
> The HTTP Auth Scheme document is a new document to provide an HTTP
> authentication scheme for Privacy Pass redemption. This can be used with
> any issuance protocol.
>
> The Issuance Protocol documents provide the protocol details for each
> issuance protocol (the PrivacyPass token protocol includes the VOPRF and
> RSA Blind Signature forms).
> --
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