Paper ReviewComputer SystemsDesign Science Research

Privacy-Preserving Digital Payments: Zero-Knowledge Proofs Meet FinTech Compliance

Financial transactions on public blockchains are transparent by designโ€”but transparency conflicts with financial privacy. ZKP-enabled payment systems allow users to prove transaction validity and regulatory compliance without revealing amounts, counterparties, or account balances.

By Sean K.S. Shin
This blog summarizes research trends based on published paper abstracts. Specific numbers or findings may contain inaccuracies. For scholarly rigor, always consult the original papers cited in each post.

Public blockchains offer transparency, immutability, and disintermediationโ€”properties that appeal to users frustrated with traditional financial systems. But this transparency creates a privacy problem: every transaction is visible to every participant. Your salary payment, medical bill, political donation, and grocery purchase are all permanently recorded on a public ledger, linkable to your identity through increasingly sophisticated blockchain analysis techniques.

The financial industry's response cannot simply be "make everything private"โ€”regulators require visibility into transactions for anti-money laundering (AML), know-your-customer (KYC), and sanctions compliance. The tension between user privacy and regulatory transparency appears irreconcilable.

Zero-knowledge proofs resolve this tension mathematically. Meesala et al. and Solomka & Liubinskyi demonstrate systems where users can prove that their transactions satisfy regulatory requirementsโ€”identity verification, sanctions screening, transaction amount limitsโ€”without revealing the transaction details themselves. The regulator receives cryptographic assurance of compliance; the user retains financial privacy.

The Architecture of Private Compliance

The system operates through a separation of concerns:

Off-chain KYC verification: A trusted KYC provider verifies the user's identity through standard processes (document verification, biometric checks). The provider issues a cryptographic attestationโ€”a digital certificate that confirms "this person has been KYC-verified"โ€”without the blockchain ever seeing the identity documents.

ZKP transaction authorization: When the user initiates a transaction, they generate a zero-knowledge proof that demonstrates:

  • They hold a valid KYC attestation (identity verified)
  • The transaction amount is within permitted limits
  • The counterparty is not on sanctions lists
  • The source of funds is from a verified account
The proof is verified by the blockchain's smart contract. If valid, the transaction proceeds. If invalid, the transaction is rejected. At no point does the blockchainโ€”or any third partyโ€”learn the user's identity, the transaction amount, or the counterparty's identity.

Selective disclosure for audit: When a regulator requires access to specific transactions (under court order or regulatory mandate), the user can generate a selective disclosure proofโ€”revealing only the specific information the regulator requests while keeping everything else private. This is more granular than the binary choice between full transparency and full opacity.

The Regulatory Challenge

The technical capability is clear. The regulatory acceptance is not. Financial regulators are accustomed to direct access to transaction data. Replacing data access with mathematical proofs requires regulators to trust cryptographic verificationโ€”a significant cultural and institutional shift.

Solomka & Liubinskyi address this by designing their framework as a minimum viable product that demonstrates regulatory compliance through ZKPs on a real blockchain network. The goal is not to convince regulators through theoretical arguments but through working demonstrations that show compliance can be maintainedโ€”and even improvedโ€”through cryptographic verification.

The improvement argument is compelling: current KYC data is stored in centralized databases at financial institutionsโ€”honeypot targets for data breaches. ZKP-based compliance eliminates these centralized stores, reducing the data breach surface while maintaining compliance assurance. The security benefit of ZKP is not just privacyโ€”it is reduced attack surface.

Claims and Evidence

<
ClaimEvidenceVerdict
ZKP enables regulatory compliance without transaction data exposureMathematical proof construction and MVP demonstrationโœ… Supported
Selective disclosure provides regulators with necessary audit capabilitySelective ZKP disclosure mechanism demonstratedโœ… Supported
ZKP reduces data breach risk by eliminating centralized KYC storesArchitectural argument; no centralized data to breachโœ… Supported (by design)
Financial regulators accept ZKP-based complianceNo regulatory jurisdiction has formally accepted ZKP complianceโŒ Not yet accepted
ZKP computation is efficient enough for real-time paymentsProof generation latency varies; optimization is ongoingโš ๏ธ Improving

Open Questions

  • Regulatory sandboxes: Which jurisdictions will be the first to allow ZKP-based financial compliance in regulatory sandboxes? Singapore, Switzerland, and the UK have progressive FinTech regulatory frameworks.
  • Interoperability: Different ZKP systems use different proof systems (zk-SNARKs, zk-STARKs, Plonk). Can proofs from one system be verified by another? Financial interoperability requires cryptographic interoperability.
  • Post-quantum security: Current ZKP systems rely on cryptographic assumptions (discrete logarithm, elliptic curve) that quantum computers may break. Are there ZKP constructions that remain secure in a post-quantum world?
  • User experience: Generating ZKPs requires computational resources on the user's device. For mobile payments, the proof generation must be fast enough to not degrade the payment experience. What is the acceptable latency budget?
  • What This Means for Your Research

    For FinTech researchers, ZKP-based compliance represents a fundamental redesign of financial privacy architectureโ€”from "collect data and restrict access" to "verify properties and never collect data." This architectural shift requires new thinking about what regulators actually need (compliance assurance) versus what they currently receive (raw data).

    For cryptography researchers, the financial application imposes concrete performance requirements (proof generation in seconds, verification in milliseconds) that drive protocol optimization. Financial ZKPs must be efficient, auditable, and legally defensibleโ€”constraints that academic ZKP research does not always address.

    References (2)

    [1] Meesala, S., Gupta, D., Challa, P. et al. (2026). Zero-Knowledge Proofโ€“Enabled Privacy Preservation for Secure Digital Payments in FinTech Blockchain. IEEE ICMCSI.
    [2] Solomka, I. & Liubinskyi, B. (2025). Zero-knowledge proof framework for privacy-preserving financial compliance. Mathematical Modeling and Computing.

    Explore this topic deeper

    Search 290M+ papers, detect research gaps, and find what hasn't been studied yet.

    Click to remove unwanted keywords

    Search 8 keywords โ†’