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Fast, private and regulated payments in asynchronous networks
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <link href="/css/dist/css/bootstrap.min.css" rel="stylesheet"> <title>Fast, private and regulated payments in asynchronous networks</title> <link rel="stylesheet" href="/css/eprint.css?v=10"> <link rel="shortcut icon" href="/favicon.ico" type="image/x-icon" /> <link rel="apple-touch-icon" href="/img/apple-touch-icon-180x180.png" /> <style> a.toggle-open:after { content:' -'; font-weight: 800; } a.toggle-closed:after { content: " ›"; font-weight: 800; } .paper-abstract { white-space: pre-wrap; } #metadata dt { margin-top: 1rem; } #metadata dt + dd { /* gap between dt and first dd */ margin-top: .75rem; } #metadata dd { margin-left: 2rem; } #metadata dd.keywords { padding-bottom: .5rem; } span.authorName { margin-top: .5rem; font-style: italic; } </style> <script> MathJax = { tex: { inlineMath: [['$', '$'], ['\\(', '\\)']], displayMath: [ ['$$','$$'], ["\\[","\\]"] ], processEnvironments: false }, loader: { load: [ "ui/safe", "ui/lazy", ], }, options: { safeOptions: { allow: { URLs: "none", classes: "safe", cssIDs: "safe", styles: "safe", }, }, } }; </script> <script id="MathJax-script" async src="/js/mathjax/tex-chtml.js"></script> <meta name="citation_title" content="Fast, private and regulated payments in asynchronous networks"> <meta name="citation_author" content="Maxence Brugeres"> <meta name="citation_author" content="Victor Languille"> <meta name="citation_author" content="Petr Kuznetsov"> <meta name="citation_author" content="Hamza Zarfaoui"> <meta name="citation_journal_title" content="Cryptology ePrint Archive"> <meta name="citation_publication_date" content="2025"> <meta name="citation_pdf_url" content="https://eprint.iacr.org/2025/098.pdf"> <meta property="og:image" content="https://eprint.iacr.org/img/iacrlogo.png"/> <meta property="og:image:alt" content="IACR logo"/> <meta property="og:url" content="https://eprint.iacr.org/2025/098"> <meta property="og:site_name" content="IACR Cryptology ePrint Archive" /> <meta property="og:type" content="article" /> <meta property="og:title" content="Fast, private and regulated payments in asynchronous networks" /> <meta property="og:description" content="We propose a decentralized asset-transfer system that enjoys full privacy: no party can learn the details of a transaction, except for its issuer and its recipient. Furthermore, the recipient is only aware of the amount of the transaction. Our system does not rely on consensus or synchrony assumptions, and therefore, it is responsive, since it runs at the actual network speed. Under the hood, every transaction creates a consumable coin equipped with a non-interactive zero-knowledge proof (NIZK) that confirms that the issuer has sufficient funds without revealing any information about her identity, the recipient's identity, or the payment amount. Moreover, we equip our system with a regulatory enforcement mechanism that can be used to regulate transfer limits or restrict specific addresses from sending or receiving funds, while preserving the system's privacy guarantees. Finally, we report on Paxpay, our implementation of Fully Private Asset Transfer (FPAT) that uses the Gnark library for the NIZKs. In our benchmark, Paxpay exhibits better performance than earlier proposals that either ensure only partial privacy, require some kind of network synchrony or do not implement regulation features. Our system thus reconciles privacy, responsiveness, regulation enforcement and performance." /> <meta property="article:section" content="APPLICATIONS" /> <meta property="article:modified_time" content="2025-01-22T09:01:00+00:00" /> <meta property="article:published_time" content="2025-01-22T09:01:00+00:00" /> <meta property="article:tag" content="Anonymous" /> <meta property="article:tag" content="Asynchronous System" /> <meta property="article:tag" content="CBDC" /> <meta property="article:tag" content="NIZK" /> <meta property="article:tag" content="Payment System" /> <meta property="article:tag" content="Privacy" /> <meta property="article:tag" content="Regulation" /> <meta property="article:tag" content="Scalability" /> <meta property="article:tag" content="zk-SNARK" /> </head> <body> <noscript> <h1 class="text-center">What a lovely hat</h1> <h4 class="text-center">Is it made out of <a href="https://iacr.org/tinfoil.html">tin foil</a>?</h4> </noscript> <div class="fixed-top" 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class="col-md-7 col-lg-8 pe-md-5"> <h4>Paper 2025/098</h4> <h3 class="mb-3">Fast, private and regulated payments in asynchronous networks</h3> <div class="author"><span class="authorName">Maxence Brugeres</span><a class="ms-1" target="_blank" href="https://orcid.org/0009-0003-3184-8696"><img class="align-baseline orcidIcon" src="/img/orcid.svg"></a><span class="affiliation">, Laboratoire Traitement et Communication de l’Informationo</span><span class="affiliation">, Institut Polytechnique de Paris</span><span class="affiliation">, Forvis Mazars</span></div> <div class="author"><span class="authorName">Victor Languille</span><span class="affiliation">, Laboratoire Traitement et Communication de l’Information</span><span class="affiliation">, Institut Polytechnique de Paris</span><span class="affiliation">, EDF R&D</span></div> <div class="author"><span class="authorName">Petr Kuznetsov</span><a class="ms-1" target="_blank" href="https://orcid.org/0000-0003-1148-1228"><img class="align-baseline orcidIcon" src="/img/orcid.svg"></a><span class="affiliation">, Laboratoire Traitement et Communication de l’Information</span><span class="affiliation">, Institut Polytechnique de Paris</span></div> <div class="author"><span class="authorName">Hamza Zarfaoui</span><span class="affiliation">, Laboratoire Traitement et Communication de l’Information</span><span class="affiliation">, Institut Polytechnique de Paris</span></div> <h5 class="mt-3">Abstract</h5> <p style="white-space: pre-wrap;">We propose a decentralized asset-transfer system that enjoys full privacy: no party can learn the details of a transaction, except for its issuer and its recipient. Furthermore, the recipient is only aware of the amount of the transaction. Our system does not rely on consensus or synchrony assumptions, and therefore, it is responsive, since it runs at the actual network speed. Under the hood, every transaction creates a consumable coin equipped with a non-interactive zero-knowledge proof (NIZK) that confirms that the issuer has sufficient funds without revealing any information about her identity, the recipient's identity, or the payment amount. Moreover, we equip our system with a regulatory enforcement mechanism that can be used to regulate transfer limits or restrict specific addresses from sending or receiving funds, while preserving the system's privacy guarantees. Finally, we report on Paxpay, our implementation of Fully Private Asset Transfer (FPAT) that uses the Gnark library for the NIZKs. In our benchmark, Paxpay exhibits better performance than earlier proposals that either ensure only partial privacy, require some kind of network synchrony or do not implement regulation features. Our system thus reconciles privacy, responsiveness, regulation enforcement and performance.</p> </div> <div id="metadata" class="col-md-5 col-lg-4 ps-md-5 mt-4 mt-md-0"> <h5>Metadata</h5> <dl> <dt> Available format(s) </dt> <dd> <a class="btn btn-sm btn-outline-dark" href="/2025/098.pdf"> <img class="icon" src="/img/file-pdf.svg">PDF</a> </dd> <dt>Category</dt> <dd><a href="/search?category=APPLICATIONS"><small class="badge category category-APPLICATIONS">Applications</small></a></dd> <dt>Publication info</dt> <dd>Preprint. </dd> <dt>Keywords</dt> <dd class="keywords"><a href="/search?q=Anonymous" class="me-2 badge bg-secondary keyword">Anonymous</a><a href="/search?q=Asynchronous%20System" class="me-2 badge bg-secondary keyword">Asynchronous System</a><a href="/search?q=CBDC" class="me-2 badge bg-secondary keyword">CBDC</a><a href="/search?q=NIZK" class="me-2 badge bg-secondary keyword">NIZK</a><a href="/search?q=Payment%20System" class="me-2 badge bg-secondary keyword">Payment System</a><a href="/search?q=Privacy" class="me-2 badge bg-secondary keyword">Privacy</a><a href="/search?q=Regulation" class="me-2 badge bg-secondary keyword">Regulation</a><a href="/search?q=Scalability" class="me-2 badge bg-secondary keyword">Scalability</a><a href="/search?q=zk-SNARK" class="me-2 badge bg-secondary keyword">zk-SNARK</a></dd> <dt>Contact author(s)</dt> <dd><span class="font-monospace"> maxence brugeres<span class="obfuscate"> @ </span>telecom-paris fr<br>victor languille<span class="obfuscate"> @ </span>telecom-paris fr </span> </dd> <dt>History</dt> <dd>2025-01-22: approved</dd> <dd>2025-01-22: received</dd> <dd><a rel="nofollow" href="/archive/versions/2025/098">See all versions</a></dd> <dt>Short URL</dt> <dd><a href="https://ia.cr/2025/098">https://ia.cr/2025/098</a></dd> <dt>License</dt> <dd><a rel="license" target="_blank" href="https://creativecommons.org/licenses/by-nc-nd/4.0/"> <img class="licenseImg" src="/img/license/CC_BY_NC_ND.svg" alt="Creative Commons Attribution-NonCommercial-NoDerivs" title="Creative Commons Attribution-NonCommercial-NoDerivs"><br> <small>CC BY-NC-ND</small> </a> </dd> </dl> </div> </div> <p class="mt-4"><strong>BibTeX</strong> <button id="bibcopy" class="ms-2 btn btn-sm btn-outline-dark" aria-label="Copy to clipboard" onclick="copyBibtex()"> <img src="/img/copy-outline.svg" class="icon">Copy to clipboard</button></p> <pre id="bibtex"> @misc{cryptoeprint:2025/098, author = {Maxence Brugeres and Victor Languille and Petr Kuznetsov and Hamza Zarfaoui}, title = {Fast, private and regulated payments in asynchronous networks}, howpublished = {Cryptology {ePrint} Archive, Paper 2025/098}, year = {2025}, url = {https://eprint.iacr.org/2025/098} } </pre> <script> var bibcopy; function triggerTooltip() { console.log('setting tooltip'); } window.onload = triggerTooltip; function copyBibtex() { let range = document.createRange(); range.selectNode(document.getElementById('bibtex')); window.getSelection().removeAllRanges(); window.getSelection().addRange(range); document.execCommand('copy'); window.getSelection().removeAllRanges(); let bibcopy = document.getElementById('bibcopy'); let copyTooltip = new bootstrap.Tooltip(bibcopy, {trigger: 'manual', title: 'Copied!'}); copyTooltip.show(); setTimeout(function() { copyTooltip.dispose(); }, 2000); } </script> </main> <div class="container-fluid mt-auto" id="eprintFooter"> <a href="https://iacr.org/"> <img id="iacrlogo" src="/img/iacrlogo_small.png" class="img-fluid d-block mx-auto" alt="IACR Logo"> </a> <div class="colorDiv"></div> <div class="alert alert-success w-75 mx-auto"> Note: In order to protect the privacy of readers, eprint.iacr.org does not use cookies or embedded third party content. </div> </div> <script src="/css/bootstrap/js/bootstrap.bundle.min.js"></script> <script> var topNavbar = document.getElementById('topNavbar'); if (topNavbar) { document.addEventListener('scroll', function(e) { if (window.scrollY > 100) { topNavbar.classList.add('scrolled'); } else { topNavbar.classList.remove('scrolled'); } }) } </script> </body> </html>