<!doctype html><html lang="en" class="no-js"><head><meta charset="utf-8"> <!-- begin SEO --><title>MOCHA: Mixnet Optimization Considering Honest Client Anonymity - Mahdi Rahimi</title><meta property="og:locale" content="en-US"><meta property="og:site_name" content="Mahdi Rahimi"><meta property="og:title" content="MOCHA: Mixnet Optimization Considering Honest Client Anonymity"><link rel="canonical" href="https://mmaahhddii1995.github.io/publication/MOCHA.md"><meta property="og:url" content="https://mmaahhddii1995.github.io/publication/MOCHA.md"><meta property="og:description" name="description" content="Mix networks (mixnets) safeguard client anonymity by forwarding traffic through multiple intermediary nodes (mixnodes), which reorder and delay messages to obscure communication patterns against a global passive adversary capable of monitoring all network transmissions. The anonymity provided by mixnets is usually assessed with a discrete-event simulator, gauging a target message’s indistinguishability among output messages. While useful for comparative analysis, this approach only approximates the mixnet’s anonymity potential. Hence, this paper sheds light on the necessity of considering the client (originator of messages) itself to gauge anonymity accurately. We further provide an algorithm (simulator) to simulate client anonymity for Loopix mixnets. We conduct experiments to optimize general Loopix mixnet parameters, considering both message and client anonymity. Our findings indicate that message anonymity often provides an upper bound and can yield misleading results for mixnet optimization, underscoring the importance of client anonymity. Additionally, we explore scenarios where client anonymity is significantly compromised due to an insufficient number of clients. To address these cases, we propose a multimixing strategy that enhances client anonymity by effectively merging varied traffic types with different mixing characteristics."><meta property="og:type" content="article"><meta property="article:published_time" content="2025-06-24T00:00:00+00:00"> <script type="application/ld+json"> { "@context" : "http://schema.org", "@type" : "Person", "name" : "Mahdi Rahimi", "url" : "https://mmaahhddii1995.github.io", "sameAs" : null } </script> <!-- end SEO --><link href="https://mmaahhddii1995.github.io/feed.xml" type="application/atom+xml" rel="alternate" title="Mahdi Rahimi Feed"> <!-- http://t.co/dKP3o1e --><meta name="HandheldFriendly" content="True"><meta name="MobileOptimized" content="320"><meta name="viewport" content="width=device-width, initial-scale=1.0"> <script> document.documentElement.className = document.documentElement.className.replace(/\bno-js\b/g, '') + ' js '; </script> <!-- For all browsers --><link rel="stylesheet" href="https://mmaahhddii1995.github.io/assets/css/main.css"> <!-- Custom CSS to force white background and black text --><link rel="stylesheet" href="https://mmaahhddii1995.github.io/assets/css/custom.css"> <!-- Force moon (dark mode) as default on page load --> <script> if (!localStorage.getItem('theme')) { document.documentElement.setAttribute('data-theme', 'light'); localStorage.setItem('theme', 'light'); } </script><meta http-equiv="cleartype" content="on"> <!-- start custom head snippets --> <!-- favicon from https://commons.wikimedia.org/wiki/File:OOjs_UI_icon_academic-progressive.svg --><link rel="apple-touch-icon" sizes="180x180" href="https://mmaahhddii1995.github.io/images/apple-touch-icon-180x180.png"/><link rel="icon" type="image/svg+xml" href="https://mmaahhddii1995.github.io/images/favicon.svg"/><link rel="icon" type="image/png" href="https://mmaahhddii1995.github.io/images/favicon-32x32.png" sizes="32x32"/><link rel="icon" type="image/png" href="https://mmaahhddii1995.github.io/images/favicon-192x192.png" sizes="192x192"/><link rel="manifest" href="https://mmaahhddii1995.github.io/images/manifest.json"/><link rel="icon" href="/images/favicon.ico"/><meta name="theme-color" content="#ffffff"/><link rel="stylesheet" href="https://mmaahhddii1995.github.io/assets/css/academicons.css"/> <!-- Support for MatJax --> <script src="https://cdnjs.cloudflare.com/polyfill/v3/polyfill.min.js?features=es6"></script> <script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script> <!-- end custom head snippets --></head><body> <!--[if lt IE 9]><div class="notice--danger align-center" style="margin: 0;">You are using an <strong>outdated</strong> browser. 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The anonymity provided by mixnets is usually assessed with a discrete-event simulator, gauging a target message’s indistinguishability among output messages. While useful for comparative analysis, this approach only approximates the mixnet’s anonymity potential. Hence, this paper sheds light on the necessity of considering the client (originator of messages) itself to gauge anonymity accurately. We further provide an algorithm (simulator) to simulate client anonymity for Loopix mixnets. We conduct experiments to optimize general Loopix mixnet parameters, considering both message and client anonymity. Our findings indicate that message anonymity often provides an upper bound and can yield misleading results for mixnet optimization, underscoring the importance of client anonymity. Additionally, we explore scenarios where client anonymity is significantly compromised due to an insufficient number of clients. To address these cases, we propose a multimixing strategy that enhances client anonymity by effectively merging varied traffic types with different mixing characteristics."><meta itemprop="datePublished" content="June 24, 2025"><div class="page__inner-wrap"><header><h1 class="page__title" itemprop="headline">MOCHA: Mixnet Optimization Considering Honest Client Anonymity</h1><p>Published in <i>ACM Workshop on Information Hiding and Multimedia Security</i>, 2025</p></header><section class="page__content" itemprop="text"><p>The contents above will be part of a list of publications, if the user clicks the link for the publication than the contents of section will be rendered as a full page, allowing you to provide more information about the paper for the reader. When publications are displayed as a single page, the contents of the above “citation” field will automatically be included below this section in a smaller font.</p><p style="font-size: smaller">Recommended citation: M. Rahimi, "MOCHA: Mixnet Optimization Considering Honest Client Anonymity." In Proceedings of the ACM Workshop on Information Hiding and Multimedia Security, pp. 98-107. 2025.<br /><a href="http://mmaahhddii1995.github.io/files/MOCHA_paper.pdf">Download Paper</a> | <a href="http://mmaahhddii1995.github.io/files/MOCHA_slides.pdf">Download Slides</a> | <a href="http://mmaahhddii1995.github.io/files/MOCHA_bib.bib">Download Bibtex</a></p></section><footer class="page__meta"></footer><section class="page__share"><h4 class="page__share-title">Share on</h4><a href="https://bsky.app/intent/compose?text=https://mmaahhddii1995.github.io/publication/MOCHA.md" class="btn btn--bluesky" title="Share on Bluesky"><i class="fab fa-bluesky" aria-hidden="true"></i><span> Bluesky</span></a> <a href="https://www.facebook.com/sharer/sharer.php?u=https://mmaahhddii1995.github.io/publication/MOCHA.md" class="btn btn--facebook" title="Share on Facebook"><i class="fab fa-facebook" aria-hidden="true"></i><span> Facebook</span></a> <a href="https://www.linkedin.com/shareArticle?mini=true&url=https://mmaahhddii1995.github.io/publication/MOCHA.md" class="btn btn--linkedin" title="Share on LinkedIn"><i class="fab fa-linkedin" aria-hidden="true"></i><span> LinkedIn</span></a> <a href="https://x.com/intent/post?text=https://mmaahhddii1995.github.io/publication/MOCHA.md" class="btn btn--x" title="Share on X"><i class="fab fa-x-twitter" aria-hidden="true"></i><span> X (formerly Twitter)</span></a></section><nav class="pagination"> <a href="https://mmaahhddii1995.github.io/publication/LAMP.md" class="pagination--pager" title="LAMP: Lightweight Approaches for Latency Minimization in Mixnets with Practical Deployment Considerations ">Previous</a> <a href="https://mmaahhddii1995.github.io/publication/PVSS.md" class="pagination--pager" title="Pre-constructed publicly verifiable secret sharing and applications ">Next</a></nav></div></article></div><div class="page__footer"><footer> <!-- Sitemap & follow removed --> <!-- Footer removed --></footer></div><script src="https://mmaahhddii1995.github.io/assets/js/main.min.js"></script></body></html>
