Many of you have probably seen your ad costs (CPCs) shoot up while your organic search traffic drops after Google’s March 2026 Core Update. Google’s March 2026 Core Update. This is mainly because Google’s algorithms are now obsessed with one thing. E-E-A-T (Experience, Expertise, Authoritativeness, and Trustworthiness). This creates a big problem for people who care about privacy: How do you prove you are an expert without giving away all your personal data to a tracker? Yes, there is a secret weapon for marketers and developers, called Zero-Knowledge Proofs (ZKPs). Originally used in the blockchain world, ZKPs are now being used to protect data while proving credentials. They allow you to win ad auctions and show your authority without ever having to sacrifice your privacy. Why Your "Thin Content" is Tanking? After the recent update, we have seen a thin content spiking the CPCs by over 40%. Google is now penalizing low-trust websites in real-time. If you are running a SaaS campaign and trying to reach developers, "Trust me, I’m an engineer" does not work anymore. Google needs proof. In the past, marketers proved their authority using cookies, trackers, and invasive data collection. But today, in a privacy-first world, these old ways just annoy users and don't work as well. The new solution to this is to let the user’s own browser prove their expertise (client-side) without sending their private data to a central server. How the Technology Works A ZKP allows one party (the prover) to prove to another (the verifier) that a statement is true without revealing any information or data. In the advertising world, we are relying heavily on SNARKs (Succinct Non-interactive ARguments of Knowledge). Using simple tools like Circom or Halo2, we can build circuits that can verify specific traits. We can check whether a user has written over 100 pieces of code or has a verified expert badge. In simplified terms, the process looks like this: A circuit defines the condition (for example: commits × publications > threshold). The browser generates a proof locally. The ad exchange verifies the proof instantly. A circuit defines the condition (for example: commits × publications > threshold). The browser generates a proof locally. The ad exchange verifies the proof instantly. The result? You get a "Verified Expert" badge on your page backed by unbreakable math. Google’s systems recognize it as a real signal of trust. Further, this improves your Quality Score, which helps to lower your ad costs and boosts your rankings. Boosting Quality Scores by 30% Adding Zero-Knowledge Proofs (ZKPs) to Google Ads can actually improve campaign performance. Agencies have started to add these proofs as custom signals in Performance Max (PMax) campaigns. When they do this, they see Quality Scores increasing by around 20–40%. Performance Max (PMax) campaigns Moreover, Google has made this easier with its “Longfellow” ZKP libraries in 2025, which help them to handle the heavy cryptography behind these proofs. Basically, your landing page or browser generates proof that confirms the user is a verified senior developer, without sharing any personal information. The Loyalty Loop The same technology that improves ads can help to improve loyalty programs. We all know the pain of loyalty programs. You have to create accounts for every brand just to earn points or get discounts. After a while, you will end up with dozens of logins and companies storing lots of your personal data. But with ZKP technologies like Semaphore or ZK Email, you can prove that you are qualified for a reward without letting out your private data. This makes loyalty programs more flexible. For example, let’s say you wrote technical articles on HackerNoon and received a verified contributor badge using the Ethereum Attestation Service (EAS). That badge could automatically unlock benefits with partner companies, like a discount on a developer SaaS tool. Ethereum Attestation Service (EAS) Your badge simply proves that you meet the requirement. No identity sharing. No massive databases of customer data. No complicated sign-ups. Here Is The Catch! I would be lying if I said that this technology is very easy to use. Agencies that are trying to move from collecting data to building trust systems face a few challenges. Proof Speed: On cheaper smartphones, generating a proof can take around 500ms. Developers are improving this by batching proofs with Risc Zero, reducing the time to about 50ms. The Skill Gap: Writing ZKP circuits with Circom is very different from normal web development. Many agencies either train their teams quickly or hire experts, which can cost around $10k per campaign. UX Issues: People don’t like seeing a wallet connection pop-up every time they interact with an ad. The best solution is to use WebAuthn, which works quietly in the background. Proof Speed: On cheaper smartphones, generating a proof can take around 500ms. Developers are improving this by batching proofs with Risc Zero, reducing the time to about 50ms. Proof Speed: On cheaper smartphones, generating a proof can take around 500ms. Developers are improving this by batching proofs with Risc Zero, reducing the time to about 50ms. The Skill Gap: Writing ZKP circuits with Circom is very different from normal web development. Many agencies either train their teams quickly or hire experts, which can cost around $10k per campaign. The Skill Gap: Writing ZKP circuits with Circom is very different from normal web development. Many agencies either train their teams quickly or hire experts, which can cost around $10k per campaign. UX Issues: People don’t like seeing a wallet connection pop-up every time they interact with an ad. The best solution is to use WebAuthn, which works quietly in the background. UX Issues: People don’t like seeing a wallet connection pop-up every time they interact with an ad. The best solution is to use WebAuthn, which works quietly in the background. The Verdict: Adapt or Fall Behind The old model of collecting and selling user data is slowly ending, and a new approach based on cryptographic proof is starting to rise. As Google’s algorithms focus more on E-E-A-T signals, agencies that depend only on cookies and old tracking methods may find it difficult. So, marketers can both protect their user privacy and prove their credibility using Zero-Knowledge Proofs (ZKPs). In short, the future of marketing will be more about proving trust.
