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It’s Time for Interoperable Data Clean Rooms

The IAB Tech Lab released a private audience activation specification named “Open Private Join & Activation (OPJA)” alongside the “Data Clean Rooms (DCR) Guidance” for public comments in February 2023. Since then, we have seen immense interest and received some great feedback from the industry. 

The initial draft of these two documents has been vastly improved, thanks to the feedback. Today, we are pleased to announce the first stable release of the OPJA specification as well as DCR Guidance and Recommended Practices. DCR Providers can now start building products and features using this interoperability standard for activating private audiences.

It is recommended that people interested in the OPJA specification first read the DCR Guidance document as a general primer. These two documents work in tandem to provide guidance to buyers and sellers choosing DCR solutions and to enable vendors to build standardized and interoperable private audience activation features.

Data Clean Rooms Guidance

The document aims to improve the understanding of Data Clean Rooms in digital advertising and expected capabilities and limitations of a modern DCR solution. The document focuses on giving publishers and advertisers a clear guide to the questions they should be asking of DCR vendors. Primarily, how they can assess that a clean room product actually provides privacy preservation guarantees.

Key concepts outlined in the guide include:

  • Glossary of commonly used terms
  • The core features of a DCR
  • Advertising use cases
  • Capabilities and limitations
  • Techniques used to guarantee privacy

This document has been improved since the original version. 

Some of the key updates to this document include:

  • Clarity of the definitions in the glossary 
  • Clear delineation between a DCR and other data collaboration solutions
  • Improved description of cryptographic techniques used by clean rooms
  • Additional notes such as operational costs and description of matching techniques

You can download the DCR Guidance and Recommended Practices here

Open Private Join & Activation 1.0

Open Private Join & Activation (OPJA) is a novel protocol that enables advertisers to activate audiences with their first party data without leaking private information. It achieves this by using cryptographic techniques and Privacy Enhancing Technologies (PETs) including public-key cryptography, private set intersection, and commutative encryption. 

The OPJA specification has been solidified and deemed ready for release and implementation. There were key updates to the document to improve ease of implementation and interoperability with other standards.

Some of the key updates include:

  • Use of ads.cert 2.0 as the key management system
  • Corrected diagrams to better illustrate private set intersection implementation
  • Guidance on how to properly generate a match transaction identifier
  • Explicit requirements for protecting input data including salting, hashing, and encryption
  • Clarification for the use case of the initial specification, which is audience activation

The most important change was using the ads.cert call sign public-key management specification. Ads.cert is a key management system that is fully decentralized and uses DNS entries for the publication and rotation of cryptographic keys. 

You can download the OPJA specification here.

Industry Support

InfoSum provided the initial draft for the Data Clean Rooms Guidance as a pioneer within the Data Clean Rooms and Data Collaboration ecosystem. InfoSum is a proud partner and active contributor to the IAB Tech Lab, working with all the valuable contributors to solve and standardize the industry’s biggest challenges. 

“The democratization of data is a critical next step that we all need to take seriously as a unified industry to ensure a sustainable future,” said Devon DeBlasio, VP Global Product Marketing at InfoSum. “In order for the safe and secure utilization of valuable assets such as first-party customer data, we must ensure that all parties are aware of the baseline requirements for connectivity, permissioning, use, and privacy protection. First-party data will only become more valuable as third-party identifiers fall off and privacy expectations rise. We are pleased to see the 1.0 release of the Data Clean Room Guide and OPJA protocol as important first steps towards greater knowledge, power, control, and protection over first-party data.”

The Magnite team were important key contributors to the Data Clean Rooms Guidance & OPJA specification. A lot of their contributions are based on operating a clean room at scale. Their clean room allows sellers and buyers to match data sets without revealing any private information.

Magnite has committed to implement OPJA into their Data Clean Room product called Magnite Match. 

“Magnite plans to enable OPJA-compatible matching and activation with Magnite Match. Magnite Match will leverage commutative encryption to match data and will allow generation of encrypted labels that are ready for activation with any DSP that supports OPJA.” said Andrei Lapets, VP Engineering & Applied Cryptography at Magnite.

Their commitment brings OPJA from the proposal realm to being a real protocol available to be used. Buyers and sellers will soon be able to activate audiences using a standardized solution, making their workflows easier and simpler to maintain.

Optable’s team was a leading contributor in the development of the OPJA specification and the Data Clean Rooms Guidelines. Their contribution is motivated by the clear need for interoperability in the media and advertising industry.

“We believe that scaling data collaboration in media and advertising requires interoperability, and that for interoperability to be realized we need open standards,” said Bosko Milekic, CPO and co-founder at Optable. “Today we are announcing Optable’s commitment to supporting OPJA. This means enabling secure activation via OPJA’s encrypted labels, and developing activation matching integrations with our partners. In the near future, any SSP, DSP, or ad server supporting OPJA will be able to activate privately matched audiences from Optable.”

Optable’s data collaboration platform enables advertisers, publishers, and retail media to connect private user data for advertising. The company is a proud member of the IAB Tech Lab and is committed to the development and support of open standards for advertising.

What’s Next

With the release of the DCR Guidance, publishers, advertisers, and DCR vendors can speak a common language and have a standard way of understanding data clean room products. 

With OPJA 1.0 the adtech ecosystem has an interoperable industry standard with which to privately activate audiences. This is an important key step towards enabling key features that buyers need to reach audiences while respecting their privacy. Vendors can now implement the specification while their users can rest assured they’re using an industry vetted standard.

In the near future, Tech Lab will continue to provide implementation guidance and technical specifications, and to help drive adoption and innovation in Data Clean Rooms privacy technology. We look forward to continuing to work with industry leaders to pave a way toward a more private and secure advertising future.

You can download and learn more about our Data Clean Rooms initiatives here


Miguel Morales
Director, Addressability & Privacy Enhancing Technologies (PETs)
IAB Tech Lab