Mozilla and Meta have teamed up in one of the most unlikely pairings, in an effort to create privacy-respecting ad tech.

The advertising industry is currently caught in a dilemma between mining the information it needs to be profitable and respecting user privacy. The two have generally been mutually exclusive, with privacy losing out — at least until recently. Efforts by Apple to improve privacy and give users options to reduce how much companies can track their activity have made a significant dent in many ad companies’ business, including Meta.

Mozilla and Meta appear to be solving one of the biggest issues in the advertising vs privacy debate, how to effectively deal with attribution, an important quantifier in helping advertisers know how effective their campaigns are.

Mozilla’s Martin Thomson described the two companies’ solution in a blog post:

For the last few months we have been working with a team from Meta (formerly Facebook) on a new proposal that aims to enable conversion measurement – or attribution – for advertising called Interoperable Private Attribution, or IPA.

IPA aims to provide advertisers with the ability to perform attribution while providing strong privacy guarantees. IPA has two key privacy-preserving features. First, it uses Multi-Party Computation (MPC) to avoid allowing any single entity — websites, browser makers, or advertisers — to learn about user behavior. Mozilla has some experience with MPC systems as we’ve deployed Prio for privacy-preserving telemetry. Second, it is an aggregated system, which means that it produces results that cannot be linked to individual users. Together these features mean that IPA cannot be used to track or profile users.

The key to IPA’s success will be whether enough companies adopt it. Having Mozilla and Meta — two organizations on the extreme opposite ends of the privacy spectrum — collaborating on it is sure to make other companies take notice.