Using Zero Knowledge Proof in Marketing, the Good, the Bad, the Ugly

Zero-Knowledge Proofs (ZKPs) sound like something pulled out of a cryptography textbook, but they’re quietly becoming one of the most important technologies shaping the future of data-driven marketing. A ZKP allows a customer to prove something is true — age, location, income bracket, purchase eligibility, membership status — without revealing the underlying data. In a world where privacy laws tighten every year and consumer trust declines, this offers something marketers have always struggled to balance: personalization without intrusion.

What makes ZKPs fascinating is how they overturn the traditional data exchange. For decades, brands asked customers to hand over buckets of personal data in return for better experiences. The problem is that too much data collection has created consumer fatigue. A Salesforce study found that 57% of customers feel uneasy with how companies use their data, and Cisco’s 2023 Consumer Privacy Benchmark report showed that 26% now delete apps purely over privacy concerns. With regulations like GDPR, CCPA, and India’s DPDP Act rising, companies are under pressure to reduce data collection without sacrificing personalization. Zero-Knowledge Proofs offer a way to do both.

One of the earliest real-world uses comes from the financial sector. Mastercard tested ZKP-based age verification in Europe, where customers could prove they were above 18 to make certain transactions — without sharing their birth date. This drastically reduced friction and eliminated the need for sensitive data storage. Mastercard reported an improvement in user trust and significant compliance benefits, especially for markets like alcohol delivery and digital goods.

Marketing teams are paying attention. Imagine running a targeted campaign for premium credit cards requiring a minimum income bracket. Traditionally, companies either collect income details or infer them using behavioral proxies. Both approaches risk stereotyping or privacy violations. A ZKP flips the model. A customer’s digital wallet could confirm they fall within the required income band without exposing the actual amount. The brand gets smart targeting; the customer retains control. It’s the closest thing to a win-win marketing has seen in years.

ZKPs are also being experimented with in loyalty programs. Starbucks, Sephora, and Nike run huge loyalty ecosystems with data-heavy membership models. But customers increasingly hesitate to share detailed preferences or personal identifiers. A ZKP-based loyalty system could allow users to prove they qualify for a Gold tier reward without revealing their full purchase history. A fashion retailer could send a personalized style recommendation based on “verified preference traits” instead of granular behavioral logs. This creates personalization without surveillance — a refreshing change in an industry notorious for tracking too much.

However, ZKPs aren’t flawless. One major challenge is complexity. Most marketing teams don’t have cryptography engineers on standby. Implementing ZKPs requires blockchain infrastructure or specialized protocols. Companies like Polygon, zkSync, and StarkWare are building scalable systems, but integrating those into existing MarTech stacks can feel like inserting a spaceship engine into a hatchback. A Gartner report in 2023 noted that only 3% of global brands currently experiment with ZKP frameworks, mainly due to technical barriers and lack of awareness.

Another downside is performance. ZKPs can be computationally expensive. While “zk-SNARKs” and “zk-STARKs” have made enormous strides, real-time marketing requires millisecond-level decisions. If a proof takes too long to generate, targeted ads or personalized recommendations fail to deliver their core value — speed. This is improving, but it’s still a bottleneck.

There’s also a philosophical challenge: ZKPs give customers more control, but marketers have historically built their models around maximizing data capture. Shifting from “collect everything” to “prove what’s needed” requires not just new tools but a new mindset. Teams must redesign customer journeys, rethink segmentation, and adopt privacy-first analytics. This may feel uncomfortable for companies used to running hyper-personalized campaigns based on rich behavioral histories.

The ugly side emerges when ZKPs are used poorly. If a brand claims “privacy by design” but uses ZKPs merely as a marketing gimmick, consumer skepticism could backlash. Much like “greenwashing,” we may soon see “privacy-washing,” where companies promote ZKP usage while still collecting excessive data. Transparency becomes crucial. Customers don’t want cryptographic jargon; they want to know what’s collected, what’s proven, and what stays private. Brands that fail to communicate this clearly risk losing trust — the very thing ZKPs are meant to protect.

Still, the benefits are too significant to ignore. ZKPs can help marketers verify purchase eligibility, build privacy-preserving recommendation systems, run compliant age-gated campaigns, detect bots without invasive device tracking, and even anonymize attribution models. Apple’s SKAdNetwork and Google’s Privacy Sandbox hint at the same future — where personal data stays with the user, and brands work with verified proofs instead of raw identifiers.

Marketing’s relationship with data is undergoing a transformation. Over the last decade, brands moved from demographic targeting to behavioral targeting to AI-driven psychographic targeting. Now the pendulum swings back toward restraint. ZKPs represent a new frontier — personalization without exposure, segmentation without surveillance, insight without intrusion. If marketers can embrace this technology thoughtfully, it may redefine customer trust in the age of AI.

• Ethereum ZK-SNARKs - https://ethereum.org/en/developers/docs/privacy/zk-snarks

• Zcash zk technology - https://z.cash/technology

• IBM blockchain privacy - https://www.ibm.com/topics/blockchain