Privacy is necessary for an open society in the electronic age. As more of our lives move online, we increasingly rely on digital systems to verify who we are, what we’re allowed to do, and whether information can be trusted. Traditionally, this verification has required sharing more data than we’d like - personal details, transaction histories, or sensitive business information.

Zero-knowledge proof (ZK) technology offers a fundamentally different approach. It allows someone to prove that something is true without revealing the underlying data itself. This idea, once mostly theoretical, is now being actively used in blockchain systems, identity solutions, and privacy-preserving applications.This technology is the cornerstone of the ZK Credo and constitutes a fundamental part of the digital ecosystem of ZKsync.

This blogpost introduces what zero-knowledge proofs are, how they work at a high level and why they matter and was published to educate on the concept of zero-knowledge proofs in order to make this technology more accessible and understandable to the general public and everyone interested in privacy-concealing, censorship-resistant and trustless systems.

What Is Zero-Knowledge Proof Technology?

A zero-knowledge proof is a cryptographic method that allows one party (the prover) to convince another party (the verifier) that a statement is true - without revealing any additional information beyond the fact that the statement is true.

In simpler terms, you can prove you know something - or that you meet a condition - without showing the thing itself.

For example:

  • Proving you are over 18 without revealing your exact birthdate
  • Proving you fulfill the requirements for health insurance coverage without actually revealing sensitive (health) data
  • Proving a transaction is valid without revealing the amounts or participants
  • Proving a computation was done correctly without re-running it

Zero-knowledge proofs were first proposed in the 1980s as a cryptographic concept. What’s changed recently is that advances in mathematics, computing power, and blockchain infrastructure have made them practical at scale.

How Do Zero-Knowledge Proofs Work?

At a high level, zero-knowledge proofs rely on mathematics to encode a statement and its verification into a form that can be checked efficiently.

While the underlying math is complex, the core idea can be broken down into three essential properties:

  1. Completeness: If the statement is true and the prover follows the rules, the verifier will be convinced.
  2. Soundness: If the statement is false, a dishonest prover cannot trick the verifier (except with extremely small probability).
  3. Zero-knowledge: The verifier learns nothing beyond the truth of the statement—no hidden data, no extra clues.

In modern systems, this usually works as follows:

  • A computation or rule (for example: “this transaction follows the protocol rules”) is expressed mathematically.
  • The prover generates a cryptographic proof that the computation was performed correctly.
  • The verifier checks the proof using a small, fast verification step—without needing to see the original data or redo the computation.

Many blockchain-based zero-knowledge proof systems use specialized proof systems (such as SNARKs or STARKs) designed to make verification fast and scalable.

Understanding the Benefits of ZK Technology

Zero-knowledge proofs are powerful because they change the trade-offs between privacy, trust, and efficiency. In many digital systems today, users are forced to overshare data simply to access services or prove eligibility. Current systems are also widely dependent on centralized data holders, heightening the risk of data breaches, surveillance, and misuse.

Zero-knowledge proofs can fix this.

Privacy & Sovereignty

Privacy is not just about secrecy; the ability of individuals and organizations to maintain agency and control over their data and actions, rather than relying entirely on centralized intermediaries.

Zero-knowledge proofs allow verification without disclosure. Instead of sharing raw data, users share cryptographic proofs.

With zero-knowledge proofs, users can verify claims independently while the respective systems don’t need to store or control sensitive user data. This way, trust shifts from institutions to cryptographic guarantees.

Example Use Cases:

  • Digital Identity: Prove you are a citizen, resident, or over a certain age without revealing your full identity or ID number.
  • Financial Transactions: Prove a payment is valid and compliant without exposing transaction details to the public.
  • Decentralized Governance: Participants can prove voting eligibility or participation without revealing identities or voting histories.
  • Healthcare: Prove eligibility for treatment or insurance without revealing medical history.

Security

Zero-knowledge proof models reduce the dependency on centralized data holders and enables more resilient, global systems.

Example Use Cases

  • Built-in Compliance: Enables “compliance-by-design” by avoiding over-collection of data by centralized entity, reducing the risk of data breaches, surveillance, and misuse.
  • Cross-Border Systems: Verification can happen without relying on a single national or corporate authority.
  • Tamper-resistant public records: Governments or institutions can publish cryptographic proofs that records were created and maintained correctly, without exposing sensitive underlying data or relying on a single custodian.

Scalability and Efficiency

Zero-knowledge proofs compress large computations into small proofs, meaning thousands of transactions can be proven as valid with a single proof, reducing network congestion and costs.

Zero-knowledge proofs can be verified by machines and smart contracts, allowing systems to interact securely without pre-existing trust relationships and remove reliance on manual human verification.

Example Use Cases

  • High throughput payment systems: Batch and prove thousands of retail or cross-border payments at once, enabling near-instant settlement with minimal onchain fees while preserving user privacy.
  • Enterprise data sharing between organizations: Companies can prove correctness of shared data (financial statements, usage metrics, ESG reporting) to partners or regulators without revealing raw proprietary datasets.
  • Supply chain verification and audits: Prove that goods passed required checks (origin, sustainability, safety standards) across many suppliers, with a single machine-verifiable proof instead of manual audits.

Why Zero-Knowledge Proofs Matter Going Forward

Zero-knowledge proof technology represents a shift in how digital systems handle trust. As digital infrastructure continues to expand across finance, identity, governance, and beyond - ZK technology offers a way to build systems that are more private, more secure, more efficient, more user-centric and less dependent on centralized control.

While the technology is still evolving, zero-knowledge proofs are quickly moving from academic theory to real-world foundation. From a regulatory perspective, policy makers are generally cautiously optimistic about zero-knowledge technology - recognizing strong potential to strengthen privacy and secure modern digital services, but concerns around complexity, resources, regulatory fit, and institutional preparedness still currently hold back wider adoption.

Understanding the capabilities of zero-knowledge proof models helps inform the design and policy choices shaping the future of digital systems that we all rely on.

Disclaimer: Please note that this blog post is provided for educational and informational purposes only. The content herein does not constitute financial, investment, or legal advice and serves the purpose of bringing the concepts of zero-knowledge proofs to a wider audience. Furthermore, this publication is an independent analysis of zero-knowledge technology and has no official connection to, affiliation with, or endorsement of any crypto asset.