Major privacy breakthrough transforms digital advertising data sharing

Five months after its initial announcement in September 2024, the IAB Tech Lab has released the first official version of the Publisher Advertiser Identity Reconciliation (PAIR) protocol. According to a January 21, 2025 announcement, this innovative cryptographic protocol enables advertisers and publishers to securely match and activate audiences while maintaining strict privacy controls.

The PAIR protocol, originally developed by Google's Display & Video 360 team, utilizes advanced commutative encryption techniques that allow matching of encrypted user data without revealing the underlying personal information. According to Shreya Mathur, Senior Product Manager at Google, "The increased performance and privacy offered by IAB Tech Lab PAIR will raise the confidence of advertisers and publishers in using their first-party data sets."

The protocol addresses a critical challenge in digital advertising as traditional identifiers like third-party cookies become unavailable. According to a study by McKinsey and Company cited in the IAB Tech Lab documentation, US publishers face potential losses of USD 10 billion due to reduced personalization capabilities and challenges in activating authenticated audiences.

The technical implementation involves multiple layers of encryption using three distinct keys - a publisher key, an advertiser key, and a shared secret key that gets rotated every 30 days. This multi-key approach ensures that no single party can access the raw user data. When advertisers and publishers encrypt their datasets using this system, they can identify matching users without exposing personally identifiable information.

Bosko Milekic, Co-founder and CEO of Optable, emphasizes the significance of standardization: "With a single unified first-party audience matching and activation standard, IAB Tech Lab is paving the way toward broader industry adoption of privacy-enhancing technologies."

The protocol implementation offers three deployment options: using a single data clean room with separate tenants, employing a trusted execution environment, or utilizing two interoperable data clean rooms. Each approach maintains strict security controls while allowing flexibility based on organizational requirements.

Technical safeguards built into the protocol include mandatory key rotation schedules, restrictions on data access, and requirements for minimum dataset sizes to prevent individual user identification. The system also enforces granular match rate reporting and implements noise addition techniques to protect user privacy.

Andrei Lapets, Vice President of Engineering and Applied Cryptography at Magnite, notes: "By bringing together the best innovations and insights from existing standards, the IAB Tech Lab is creating another streamlined, broadly applicable solution that SSPs, DSPs, and data clean rooms can jointly leverage as the modern advertising technology toolkit evolves."

The PAIR protocol includes specific requirements for all participating entities. Publishers must ensure proper user consent collection and maintain URL-safe format for identifiers. Advertisers need to verify first-party data ownership and promptly handle privacy right requests. Data clean rooms must implement rigorous security controls including encryption key management and access restrictions.

Andrew Knox, Product Manager for Privacy Technology at Decentriq, highlights the protocol's interoperability benefits: "The integration of data clean room interoperability with PAIR will be a great step forward for the industry. This now has the potential to become the premier way to protect and use first-party audiences."

Miguel Morales, Director of Addressability and Privacy Enhancing Technologies at IAB Tech Lab, explains that PAIR represents the latest development from the organization's Addressability & Privacy Enhancing Technology Working Group. The protocol works alongside other recent initiatives including Data Clean Rooms Guidance and the AdMAP measurement protocol.

The release of PAIR marks a significant evolution in privacy-preserving advertising technology, providing a standardized approach for audience matching that maintains user privacy while enabling effective digital advertising in an increasingly privacy-focused landscape.