Paper 2025/1715

UltraMixer: A Compliant Zero-Knowledge Privacy Layer for Tokenized Real-World Assets

Zonglun Li, McGill University
Hong Kang, McGill University
Xue Liu, McGill University, Mohamed Bin Zayed University of Artificial Intelligence
Abstract

Real-world-asset (RWA) tokens endow underlying assets with fractional ownership and more continuous settlement, yet recording these claims on transparent public ledgers exposes flows and positions, undermining market confidentiality. Practical deployments must reconcile enforceable access control with principled privacy once assets are shielded. We present UltraMixer, a noncustodial privacy layer natively compatible with ERC-3643. Compliance is enforced at the boundary via zero-knowledge proofs of whitelist membership, while in-mixer transfers and atomic trades operate over commitments with nullifiers to prevent double-spend. A generalized UTXO encoding supports heterogeneous assets (fungible and non-fungible) under a unified commitment scheme. For selective disclosure, UltraMixer provides a verdict-only $\Delta$-Window Proof of Holding that attests to continuous ownership across a time interval without revealing balances, identities, or linkages. Gas-aware batching and composable emergency controls (pause, freeze/unfreeze, force-transfer) preserve practicality and governance. The resulting architecture delivers regulator-compatible confidentiality for permissioned RWA markets.

Metadata
Available format(s)
PDF
Category
Applications
Publication info
Preprint.
Keywords
Real-World AssetsMixing ServiceERC-3643-Compliant PrivacyRegulation
Contact author(s)
zonglun li @ mail mcgill ca
hong kang @ mail mcgill ca
xueliu @ cs mcgill ca
History
2025-09-22: approved
2025-09-21: received
See all versions
Short URL
https://ia.cr/2025/1715
License
Creative Commons Attribution-NonCommercial-ShareAlike
CC BY-NC-SA

BibTeX

@misc{cryptoeprint:2025/1715,
      author = {Zonglun Li and Hong Kang and Xue Liu},
      title = {{UltraMixer}: A Compliant Zero-Knowledge Privacy Layer for Tokenized Real-World Assets},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/1715},
      year = {2025},
      url = {https://eprint.iacr.org/2025/1715}
}
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