Subject: [Privacy-pass] Revised Timeline for PRIVACYPASS

From: Ben Schwartz <[email-masked]>
Date: Tue, 28 Sep 2021 17:07:52 -0400

Based on input from the authors of the adopted drafts, the chairs would
like to propose a revised timeline for the working group as follows:

1. Immediate priority: Symmetric Mode

The working group’s next step will be to define a “symmetric mode” for
Privacy Pass.  This mode will offer support for optional public metadata,
but will not enable the use of public verifiability.  We believe this mode
would be sufficient to support a baseline version of the corresponding work
in the W3C.

The working group will focus on developing this mode using the POPRF
algorithm, while ensuring that it is extensible to support ecosystems
containing some Issuers that use other algorithms, such as PMBTokens.

The timeline for developing the symmetric mode is as follows:

October 2021 - Revise the adopted architecture and API drafts to focus on
this mode.

November 2021 - Replace the current “protocol” draft with a simpler
“integration” draft describing how Privacy Pass in symmetric mode
incorporates cryptographic algorithms like POPRF, what properties those
algorithms must have, and how one configures Privacy Pass to use these
algorithms

February 2022 - Interoperability confirmation of standalone client and
server implementations.

March 2022 - WGLC for the HTTP API and “integration” drafts.

The working group will also continue to update the Architecture draft with
discussion of deployment issues, consolidation, and metadata analysis.

2. Future Work

There are a number of important work items that the working group intends
to pursue, but which do not currently have a specified timeline.

The following work items are paused to focus on immediate priorities, and
will be reopened as we near completion of the “symmetric mode”
specification:
 - Support for algorithms other than POPRF (e.g. PMBTokens)
 - Support for a “publicly verifiable” mode (relying on BLS or Blind RSA
signatures)

The following work items are paused pending progress on corresponding work
in the W3C:
 - Specification of application-layer requirements
 - Browser API specifications (Javascript and/or HTML)
 - WGLC for the Architecture draft

--Ben Schwartz, for the chairs