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WICG / turtledove

TURTLEDOVE
https://wicg.github.io/turtledove/
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Second-price auction in B&A #769

Open yanushP opened 1 year ago

yanushP commented 1 year ago

We are thinking how we can run Second price auction in B&A services in TEE and it look like that it will work incorrect with current api.

For example, let assume that we have 2 InterestGroups for one buyer and only one buyer participates in the auction:

InterestGroup_1 - have two ads and bids: bid_1 = 3$, bid_2 = 2$. InterestGroup_2 - have one ads and bids: bid_1 = 1$.

So, in our understanding, final bid should be - 2$(because IG1.bid_1 is amnestied until IG1.bid_2).

However, in current API of Bidding response and Auction request we have only one bid.
schema of GetBidResponse https://github.com/privacysandbox/bidding-auction-servers/blob/main/api/bidding_auction_servers.proto#L561 schema of ScoreAdsRequest https://github.com/privacysandbox/bidding-auction-servers/blob/main/api/bidding_auction_servers.proto#L861

So, it's mean that in example above we will have only two bids in auction: IG_1.bid_1 = 3$ and IG_2.bid_2 = 1$
and final bid in second price auction will be - 1$. (because we don't have any bidfloor in api).

It's look incorrect. Is it a bug? Or maybe fledge shouldn't support second-price auction at all?

JensenPaul commented 1 year ago

Protected Audience API supports second-price auctions, see highestScoringOtherBid in the Protected Audience explainer, so this issue may be exclusive to https://github.com/privacysandbox/bidding-auction-servers. Might be worth moving this issue to the related area https://github.com/privacysandbox/bidding-auction-servers/issues. @chatterjee-priyanka to confirm that's a good idea.

chatterjee-priyanka commented 1 year ago

Hi,

Thanks for the issue.

Yes. As Paul mentioned, it would be better to create B&A related issues in https://github.com/privacysandbox/fledge-docs/issues.

B&A supports Second Price auction and highestScoringOtherBid. The field is here- https://github.com/privacysandbox/bidding-auction-servers/blob/main/api/bidding_auction_servers.proto#L1088. I will make this clearer in https://github.com/privacysandbox/fledge-docs/blob/main/bidding_auction_services_api.md#timeline-and-roadmap that second price auction is supported.

B&A currently supports event level reporting, we do plan to publish an explainer soon that will cover more details.

pthaike commented 9 months ago

@JensenPaul @chatterjee-priyanka I could not find this filed highestScoringOtherBid in the link. Is there any update for this schema? And could you provide some details or sample code for supporting second price?

eysegal commented 1 month ago

Hi, what's the reason for this - "It is not reported to top-level sellers in a multi-SSP case because we expect a top-level auction in this case to be first-price auction only"?

michaelkleber commented 1 month ago

There was a bunch of discussion about second-price auctions and component seller vs top-level seller in the call on 2022-03-30.

If there are buyers and sellers interested in another type of PA auction and it's not supported by the reporting capabilities in place now, then we are happy to talk about what new options need to be added.