Setting Prebid Default for TID to off in prebid 8

[jtollestrup]

Due to privacy concerns regarding back end stitching of data utilizing the TID, the publisher committee has elected to flip the default in Prebid for TID to off and allow each publisher to make their individual determination to turn this feature on.

[dgirardi]

Is this referring to imp.ext.tid, source.tid, or both?

For source.tid this needs, in general, an update to every adapter. imp.ext.tid would be easier to toggle centrally.

[jtollestrup]

Both.

[jtollestrup]

We met with Prebid legal today and they strongly recommended that this feature be defaulted off.

[patmmccann]

TBD: should the config toggle be in activity control or its own top level flag?

[jdwieland8282]

The Identity PMC supports setting TID to off by default. The group discussed the topic in our Identity PMC mtg on 4/26.

[dgirardi]

Many adapters include auctionId as part of their payload, separately from source.tid. This is especially common for those that do not use ORTB, but not limited to them. What should we do about that? replace them with a random UUID?

[dgirardi]

Here's an alternative proposal:

• refactor every usage of auctionId that is clearly interchangeable with source.tid as discussed above;
• when it's not clear (see below), leave it untouched, and:
• when transaction ID are turned off, add a check on outgoing network requests, and forcibly cancel requests that contain auctionId.

This way, when TIDs are turned on, adapters will continue to work as if nothing changed; when they are turned off, we can have good confidence that data won't be leaked.

Otherwise we don't have a good way to deal with a large number of adapters that use a pattern like this:

Prebid.js/modules/proxistoreBidAdapter.js

Lines 26 to 30 in bc665aa

	var payload = {
	auctionId: bidRequests[0].auctionId,
	transactionId: bidRequests[0].auctionId,
	bids: sizeIds,
	website: bidRequests[0].params.website,

in this case, it's clear that transactionId is meant to be the TID and should be protected by the new control we are introducing for 8. But we do not know what to do with auctionId - removing it has a good chance to unnecessarily break it.

I'll add that IMO it's too early to turn TIDs off by default - there's a good chance that it will break so many adapters that the vast majority of publishers will be de-facto forced to turn them back on again.

[dgirardi]

The enforcement on network requests could also be made into a module - if we are OK with the default being "TID are off, but we don't know if they are actually being sent out".