A heated debate over transaction IDs (TIDs) has raged since last month when Prebid announced a major update to how it handles TIDs.
After digesting the new Prebid policy for a few weeks, the publisher ad network Raptive is now entering the fray with a proposal it hopes will satisfy both the buy side’s and sell side’s concerns about the use of TIDs, as well as Prebid’s recent changes to how TIDs are generated and shared.
The proposal, which Raptive Chief Strategy Officer Paul Bannister posted on LinkedIn today, is simple enough: Rather than sharing universal TIDs that any DSP or curator can access, publishers should instead share encrypted TIDs (or eTIDs) with an encryption key provided only to trusted demand-side partners. That way, publishers have control over whom they share valuable data with.
What’s there to debate?
Raptive’s plan would require the IAB Tech Lab to create a new OpenRTB field for eTIDs.
Raptive has had early conversations with the IAB Tech Lab and Prebid about the proposal and is seeking feedback from the industry, Bannister told AdExchanger.
“We want this to be a conversation,” he said.
Plus, as a sign of good faith to the buy side, Raptive itself will begin sharing TIDs in all bid requests, Bannister said. He anticipates that Raptive will complete this shift within the next few weeks.
But why is there so much commotion over TIDs in the first place?
Here’s the short version: TIDs are unique identifiers that are created for each programmatic auction. They’re intended to be consistent across different DSPs, SSPs and resellers so that buyers can see when multiple supply-chain paths are bidding on the same impression. In its version 8 update back in 2023, Prebid began allowing publishers to opt into sharing TIDs in each OpenRTB bid request. But, as of version 10.9.0, which went live in August, Prebid shifted to creating different TIDs for each bidder, making them less useful for finding duplicated auctions.
The buy side raged against Prebid’s decision. The IAB Tech Lab said the change was incompatible with the spirit of OpenRTB. But publishers defended the move, claiming the use of TIDs exposed too much transaction data to too many programmatic vendors.
Bannister has made his own concerns about TIDs clear, echoing other publisher complaints over TID use.
Publishers say reducing auction duplication takes away their ability to drive up bid density, which improves their yield. Publishers also worry that the buy side can use universal TIDs to reverse-engineer the different pricing floors publishers set for auctions operated by different supply-side partners – which also removes a point of leverage that publishers use to drive up inventory prices.
Plus, Bannister said, DSPs could use universal TIDs to reverse engineer confidential information on the sell side.
For example, TIDs give buyers transparency into SSP take rates, which are “contractually private information between the publisher and SSP,” he said.
Or tech vendors could use TIDs to “tie together user information that is consented through some supply paths, but not consented in others,” he said. This approach could cause publishers to run afoul of data privacy regulations like GDPR that govern who has access to data once the user consents to it being shared.
But, Bannister added, he recognizes that good-faith demand-side partners have legitimate reasons for wanting transparency into auction dynamics, like avoiding duplicated auctions. Hence the need to come up with a way to share TIDs while ensuring that only trusted and contractual partners are allowed to see certain ID data.
De-encryption in practice
So how would eTIDs work?
According to Raptive’s proposal, DSPs must engage in a reciprocal data exchange with a publisher in order to access the encryption key for that publisher’s eTIDs.
Raptive suggests that a trusted DSP should be willing to provide publishers with information about the bids they’re submitting for each eTID. This feedback process would require a framework similar to OpenRTB’s “lurl” field, which SSPs use to send DSPs data on why their bids failed to win an auction, Bannister said.
Raptive’s proposal also requires DSPs to engage proactively in multi-bidding on publisher inventory to get access to eTID encryption keys. So, rather than running internal auctions within the DSP and submitting only a single winning bid from that internal auction, DSPs would instead submit multiple bids through the publisher’s SSP. That way, the publisher has more insight into bidding dynamics and more assurance that they’re truly getting the highest bid from the DSP, Bannister said.
Raptive does not have a preference for the kind of encryption methodology; that would be up to the IAB Tech Lab and Prebid to decide, Bannister said.
However, he suggested that each DSP would get its own encryption key that could be used to de-encrypt any eTID submitted in any bid request. That way, the DSP wouldn’t have to manage different keys for different auctions.
Asked whether there’s a chance all this required de-encryption and data sharing could slow down programmatic auctions, Bannister said the de-encryption would likely be done in batches either hourly or at the end of each day, rather than in real time.
He added that, based on conversations with DSPs, the demand platforms usually don’t examine TIDs to reduce auction duplication in real time, but rather examine them in batches at regular intervals to adjust for future auctions. So, in that sense, nothing would change with the use of eTIDs rather than universal TIDs.
And, regarding the possibility that DSPs could use their buy-side leverage to simply turn off demand to any publisher or SSP that doesn’t share universal TIDs, Bannister said he has faith in the industry’s desire to collaborate on a solution that works for all sides.
“I think the DSPs are reasonable and they understand that publishers have real concerns,” he said. “I’m optimistic that they’ll say this is a solution that gets everybody to a better place.”
