Aug 30, 2021 6 min read

Private Identifier for Advertising (PIFA)

Private Identifier for Advertising (PIFA)

The following post presents a concept that does not exist today. I wanted to put this new take on identity out in the open to invite discussion, dissection, and criticism. The proposal below puts privacy-conscious users first and could live alongside other ID solutions.

We are in the midst of a tectonic shift around identity in digital advertising. The people making decisions on how we handle identity may only have their capital interests in mind, and the users these decisions impact the most have little say.

I have written the concept as a marketing page that would live on the website of the entity hosting the solution. The entity could be a single company, consortium, or decentralized autonomous organization (DAO), but I made no presumptions. I purposely omitted many details for the sake of approachability, brevity, and clarity.


The Private Identifier for Advertising (PIFA) empowers users to take control of their online identities. The current state of advertising identity management is fractured, confusing, and opaque. An anonymous identity management system gives users a way to take full control of their digital advertising identity without providing any directly identifying information.

PIFA for Consumers

Consumers can create a PIFA that they will then share with content providers in exchange for access to content or services. The user will create a profile that will, at a minimum, contain age, gender, income, and postal code. The user can optionally provide interests to obtain more relevant ads.

Creating a profile will not require any directly identifying information (name, email, etc.) from the user. The user will only provide a few required data points (age, gender, income, postal code) and will be issued a public and private key.

Users keep the private key to edit or delete a profile, and the public key is then available to share with content providers in exchange for access to their content and services.

Publishers collect the public key from the user, and ad tech providers and advertisers use the public key to access that user’s profile to deliver targeted ads to the user. Ad platforms can also use the public key to build a profile of the user based on interactions with ads or content, but users will maintain complete control of their profile.

Advantages for consumers

Contrary to most device IDs and cookies, users will only share PIFA when they choose. Website and apps can collect cookies and device IDs without consent in the United States, and companies can tie this to real world identity if the user provides those details. Since users only need to provide their public key with PIFA, they do not need to reveal any directly identifying information.

Email-based identifiers like Unified ID 2.0 provide cross-site / app anonymity — but require the user to give up a direct vector to their everyday life (email address). Privacy-conscious users may not want to sacrifice their email inbox in exchange for access to content. These users may also use email burner services which render email-based identifiers useless.

The PIFA is an anonymous alphanumeric string. Advertisers and ad systems can only link PIFA to an individual if the user provides both PIFA and linkable information. They can choose to remain anonymous by only providing a PIFA.

The user maintains control of their profile at all times and can edit or delete their profile using their private key. The user can also view all entities that have accessed their profile and selectively block future access from whichever entities they choose.

If a consumer provides a PIFA to a publisher, they will have a much more enjoyable overall experience. First, the ads displayed on the website or app will always stay relevant to the user. Second, publishers can ensure the same ads are not delivered excessively.

A built-in incentive layer rewards users when they provide their PIFA or a third party requests access to their profile. Consumers can earn tokens that they can exchange for access to ad-free experiences or premium content. Consumers can also earn tokens for providing more detailed profile information like interest categories.

Why should consumers want to use PIFA?

There are many benefits of PIFA for consumers. Consumers:

  • Want to have control over their digital identity used by advertisers and have the right to delete it
  • Want to see ads relevant to them
  • Do not want to see the same ad over and over
  • Desire privacy & anonymity
  • Do not want to share their email
  • Do not want companies linking their digital and real-world identity
  • Want free stuff

PIFA for Advertisers & Ad Tech Providers

Ad Tech providers face looming challenges in identity management. Apple's restrictions to IDFA and Google's proposed deprecation of third-party cookies have surfaced obstacles in resolving identity.

These challenges have already impacted key areas of ad delivery like frequency capping, geotargeting, audience data targeting, or conversion tracking. These ad-serving features rely on an identifier like IP address, device ID, or browser cookie.

IP Address: Not user or device-specific and offers the user no control since they cannot easily reset.
Device Advertising ID: Offers user control (resettable) but fractured. There are too many device-specific IDs, which require segregated management. Users also have to reset every device for privacy control.
Browser cookie: Third-party cookies are dying. First-party cookies require European users to opt-in (GDPR), and tracking methods are opaque to the user. User control exists but is not readily available.
Email address: Requires a user to sacrifice their inbox and provides a vector for connecting real-world identity.
PIFA: Anonymous, modifiable, and deletable by the user. The user is in complete control and has incentives to provide.

Even before the recent privacy reckoning, identity resolution relied on complex and even harmful systems. Cookie syncing slows down page loads, fingerprinting identifies users without consent, and Apple's SKAdNetwork only provides aggregate conversion information.

Several universal identity solutions are trying to solve challenges in identity management. The key negating factors in all of these solutions are:

1. No user profile info

Universal identifier solutions only provide an identifier, unlike the PIFA that can provide willingly shared information.

2. User sacrifices email

The user must provide their email address. Providing an actual real email is a non-starter for privacy-conscious users.

3. Based on fingerprinting

Some universal identity companies rely on fingerprinting to assign users an identifier. Even with consent, privacy advocates frown on this method of identification.

Advantages for advertisers and ad tech providers

Advertisers want to reach their target audience and want to maintain good faith with their potential customers. PIFA offers a privacy-focused solution for advertisers to target users in an open and transparent method.

Since a user provides a postal code, there is no need to extract an IP address. Most users do not even know ad tech companies extract their IP addresses for location targeting. Users might also not know that companies share that IP address with third-party geolocation services. They also can willfully stop collecting IP addresses for data targeting.

When users provide a PIFA, ad tech companies can use this value instead of IP address, cookies, or device IDs to frequency cap and prevent ad fatigue. The value can even solve cross-platform frequency capping.

The user will provide PIFA directly, which makes it inherently cross-platform. A user can input the id in their web browser, smartphone, tablet, or connected TV. Ad tech providers can then maintain frequency caps on anonymous users across all their devices. The cross-platform nature of PIFA also extends to data targeting.

The user will provide relevant details when creating their PIFA like age, gender, income, and postal code. Advertisers can use this information to target relevant ads to the user across any platform. Users can also provide optional interests to make ads even more relevant and to enhance their experience.

Why should advertisers & ad tech providers use PIFA?

  • Location target with ease
  • Reduce ad fatigue and over-exposure
  • Cross-platform frequency capping solved
  • Cross-platform user targeting solved
  • Data targeting solved (Age, gender, income)
  • Establish consumer good faith for focusing on privacy

PIFA for Publishers

Publishers can choose to build websites and applications that accept a PIFA from a user in exchange for access to content. Similar to the value exchange of email-based identity solutions, except that users do not have to give up their inbox and risk their email address falling into the wrong hands.

Advantages for publishers

Publishers can use PIFA to enhance their direct ad serving capabilities (such as frequency capping, location targeting, or audience targeting) or share with advertising partners via programmatic channels to enrich the value of potential impressions.

Since PIFAs contain information directly shared by the consumer, potential PIFA-enriched ad requests provide valuable opportunities for audience targeting. Rather than relying on third-party data sets whose genesis is unknown, advertisers can target user-provided identity characteristics.

User-provided data will elevate the price advertisers are willing to pay for potential impressions. Publishers can provide incentives to entice users to share their PIFA by unlocking access to premium content, opening up new features, or gamifying their experiences.

Users will appreciate publishers offering a privacy-focused identity solution and a more relevant advertising experience with fewer repeating ads.

Why should publishers use PIFA?

  • Data targeting without cookies, device identifiers or email
  • Privacy-compliant cross-platform user targeting
  • Establish good faith with users
  • Elevated advertiser CPMs with data-layered campaigns


Now back to reality. The above idea may have holes, invite scrutiny, and surface questions. Some of these questions could be:

  • Will users ever willingly share demographic information with advertisers even if it is anonymous?
  • How could anyone implement such a system?
  • Who would run this system?

Even if you believe this proposal does not make sense to you from a technical or fundamental standpoint, I hope it made you think and question current identity solutions. I also hope the digital advertising industry keeps users at the forefront of any debate about potential identity solutions.

Do you think the above concept could ever work? I would love to hear your thoughts. Feel free to reach out directly or find me on Twitter.

Photo by Alex Iby on Unsplash

Trey Titone
Trey Titone
Author of Ad Tech Explained and VP of Client Success at Logiq. Former Principal Product Manager at SpotX and Head of Product at Beachfront.
Great! You’ve successfully signed up.
Welcome back! You've successfully signed in.
You've successfully subscribed to Ad Tech Explained.
Your link has expired.
Success! Check your email for magic link to sign-in.
Success! Your billing info has been updated.
Your billing was not updated.