SPARROW Gatekeeper and hosted bidding logic

Hi,

Thanks everyone for the two days virtual F2F, I think it was very useful and that we’ve made progress. Thanks in particular to Wendy for the organization, and to all people who run presentations.

There has been two questions from Gang Wang at the end of the last session that has been rapidly answered, and Basile and I wanted to give some precisions.

The questions were, from what I recall:

  *   In the SPARROW proposal, Ad Tech companies bidding logics would be hosted on the Gatekeeper. Do you think these Ad Tech companies will agree to share this core private competency?
  *   Bidding logic might be a lot of code, changing often. How does it fit with the Gatekeeper auditing requirements?

On these:

  *   Bidding logics hosted by the Gatekeeper are private. The Gatekeeper must not share them with any other actor. Indeed, Ad Tech companies have to trust the Gatekeeper not to do so. Nevertheless, we see this as a great improvement over TURTLEDOVE, where interest-group bidding logic (or at least part of) is sent to the browser in the form of a javascript function, which, IMHO, cannot be kept private.
  *   Bidding logics provided to the Gatekeeper by Ad Tech companies only output bid values. Some provision over bid value precision has to be taken so it cannot be used to leak information (e.g.: 4 digits rounding).  But bidding logics do not output any other info, nor do they call services outside of the Gatekeeper. So there is no need for auditing on those, and update frequency only depends on Gatekeeper and Ad Tech technical considerations.

I hope it answers the questions, do not hesitate to say so if it doesn’t.

Best,
Lionel