The goal of Google's Privacy Sandbox is prevent marketers from engaging a particular audience in a particular context.
Google's Augury proposal attempts to enable consumer retargeting without any marketers receiving any identifier.
The proposed mechanism requires buyer to store audience attribute information marketers would want to later use as an input into audience creation or auction management within the web client and subsequently submit bids for all possible audience segments the web client may be eligible for.
By disclosing separate bid values for all possible audience attributes, buyers' systems must compute more information and transfer more information back to the auction system.
By disclosing separate bid values for all possible audience attributes, buyers' are leaking their intellectual property associated with they value place on particular information.