Subject: [CFRG] Request for adoption of draft-patton-cfrg-vdaf-01

From: Christopher Patton <[email-masked]>
Date: Mon, 7 Mar 2022 11:24:17 -0800

Hi all,

Those who attended the CFRG session at IETF 112 will recall a presentation
on "Verifiable Distributed Aggregation Functions (VDAFs)" [1]. VDAFs are a
family of multi-party protocols for computing aggregate statistics over
sensitive user measurements. They are designed to ensure that, as long as
at least one aggregation server executes the protocol honestly, individual
measurements are never seen by any server in the clear.

In the PPM working group [2], we're working on a protocol spec that, if
adopted, would use VDAFs as its core cryptographic component. As such, we
would appreciate the CFRG's feedback on the current draft [1]. Specifically:

1. Is the working group interested in adopting this draft?
2. Is this document mature enough for adoption?

The main development since IETF 112 is a complete specification for Prio.
We have also completed a reference implementation [3] for which there is
one compatible implementation [4]. The draft is far from finished, but we
believe it's mature enough for the CFRG to begin work on it. The next chunk
of work is to complete the specification of Poplar (formally known simply
as "Heavy Hitters" [5]). Other open issues are documented in [6].

I have asked the chairs for a chunk of time to discuss this draft at IETF
113, so we'll have a chance to discuss this then. On behalf of the authors,
I appreciate your consideration of this work.

Best,
Chris P.

[1] VDAF draft: https://datatracker.ietf.org/doc/draft-patton-cfrg-vdaf/
[2] PPM charter: https://datatracker.ietf.org/doc/charter-ietf-ppm
[3] Reference implementation of Prio3:
https://github.com/cjpatton/vdaf/blob/main/poc/vdaf_prio3.sage
[4] libprio-rs: https://github.com/abetterinternet/libprio-rs/
[5] Poplar paper: https://ia.cr/2021/017
[6] Open issues: https://github.com/cjpatton/vdaf/issues