[CFRG] Changes planned for the next VDAF draft

[Christopher Patton <[e-mail]>]

Hi CFRG,

As you may have noticed, the RG recently adopted
https://datatracker.ietf.org/doc/draft-irtf-cfrg-vdaf/. In this email I
wanted to give you a heads up about the work the authors would like to get
done before IETF 114. Please let us know if you object to any of these
changes or if there is something else you'd like to see in the next draft.

   - Complete spec for Poplar1 (as promised at IETF 113). This would
   resolve https://github.com/cfrg/draft-irtf-cfrg-vdaf/issues/22 and
   https://github.com/cfrg/draft-irtf-cfrg-vdaf/issues/44.
   - Minor improvement to Prio3 that reduces communication overhead:
   https://github.com/cfrg/draft-irtf-cfrg-vdaf/issues/39. Note that this
   scheme still requires security analysis.
   - Define syntax of DAFs, i.e., VDAFs w/o verifiability:
   https://github.com/cfrg/draft-irtf-cfrg-vdaf/issues/20. This allows us
   to avoid round trips over the network during the preparation phase in
   applications where the clients are trusted to shard their inputs properly.
   - Remove the public parameter from the syntax:
   https://github.com/cfrg/draft-irtf-cfrg-vdaf/issues/19. This feature was
   included in order to make room for VDAFs that might use public key
   cryptography. So far we have none, and the public parameter has turned out
   to be a bit of a burden for PPM, which right now is the main application of
   VDAFs.

Thanks,
Chris P.