Paper 2026/1118

AuditPay: Anonymous Payments with Controlled Oversight

Elkana Tovey, Hebrew University of Jerusalem
Yossi Gilad, Hebrew University of Jerusalem
Aviv Zohar, Hebrew University of Jerusalem
Abstract

This paper introduces AuditPay, a novel mechanism for blockchain mixers that enables controlled oversight through an ``auditing budget.’’ Auditors may monitor up to a budgeted number of addresses per epoch (e.g., an hour or a day), without revealing to users which addresses are monitored. Unlike traditional approaches that require users to voluntarily disclose viewing keys to trusted gatekeepers, AuditPay cryptographically enforces auditing compliance while preserving privacy for non-monitored user addresses and without introducing additional trust assumptions. At the core of AuditPay’s design is a selective encryption mechanism coupled with an efficient audit-key encoding scheme, enforced by a lightweight zero-knowledge proof. Users encrypt audit-relevant information under an audit key, which permits decryption only if the payment is to (or, alternatively, from) an address selected by the auditor for monitoring. We implement AuditPay as an Ethereum-based payment mixer and show through experiments on our prototype that its performance and gas-cost overheads are modest, providing a practical solution for balancing payment oversight with user privacy.

Note: This is the full version of the paper to appear at CCS 2026, including proofs omitted from the conference version.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Published elsewhere. Minor revision. Proceedings of the 2026 ACM SIGSAC Conference on Computer and Communications Security (CCS 2026)
Contact author(s)
elkana tovey @ mail huji ac il
yossigi @ cs huji ac il
avivz @ cs huji ac il
History
2026-06-02: approved
2026-05-31: received
See all versions
Short URL
https://ia.cr/2026/1118
License
Creative Commons Attribution-NonCommercial
CC BY-NC

BibTeX

@misc{cryptoeprint:2026/1118,
      author = {Elkana Tovey and Yossi Gilad and Aviv Zohar},
      title = {{AuditPay}: Anonymous Payments with Controlled Oversight},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/1118},
      year = {2026},
      url = {https://eprint.iacr.org/2026/1118}
}
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