<!doctype html><html lang="en" class="no-js"><head><meta charset="utf-8"> <!-- begin SEO --><title>OptiMix: Scalable and Distributed Approaches for Latency Optimization in Modern Mixnets - Mahdi Rahimi</title><meta property="og:locale" content="en-US"><meta property="og:site_name" content="Mahdi Rahimi"><meta property="og:title" content="OptiMix: Scalable and Distributed Approaches for Latency Optimization in Modern Mixnets"><link rel="canonical" href="https://mmaahhddii1995.github.io/publication/OptiMix.md"><meta property="og:url" content="https://mmaahhddii1995.github.io/publication/OptiMix.md"><meta property="og:description" name="description" content="Mixnets provide network-level anonymity, traded off with increased communication latency, which consequently limits their applicability to only latency-tolerant applications, shrinking the anonymity set to clients engaged in such use cases. Addressing this issue requires optimizing latency, as recently explored in LARMix (NDSS’24) and LAMP (NDSS’25) through node arrangement and strategic routing. However, these approaches are tailored to specific mixnet designs, rely on simplified models and trust assumptions, or suffer from limited practical efficiency. In contrast, OptiMix bridges these gaps by introducing a general low-latency mixnet model adaptable to all well-established designs. To this end, we first propose an efficient distributed protocol for arranging nodes in mixnets that achieves low-latency properties while maintaining unbiasability against adversaries. Second, we introduce novel strategic routing schemes that optimize communication latency. Third, we design a load-balancing algorithm that evenly distributes traffic without undermining the latency-optimized characteristics of the routing strategies. Fourth, we conduct extensive evaluations using data from the deployed Nym mixnet, demonstrating substantial latency reductions with minimal anonymity loss across various mixnet designs—achieving up to 4x performance gains over state-of-the-art solutions. Finally, considering that latency reduction incurs either anonymity degradation or increased bandwidth overhead—as stated by the anonymity trilemma—we propose a cover-routing mechanism that enables clients to benefit from low-latency mixnets without compromising anonymity, at the modest cost of generating additional cover traffic."><meta property="og:type" content="article"><meta property="article:published_time" content="2026-02-27T00:00:00+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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Addressing this issue requires optimizing latency, as recently explored in LARMix (NDSS’24) and LAMP (NDSS’25) through node arrangement and strategic routing. However, these approaches are tailored to specific mixnet designs, rely on simplified models and trust assumptions, or suffer from limited practical efficiency. In contrast, OptiMix bridges these gaps by introducing a general low-latency mixnet model adaptable to all well-established designs. To this end, we first propose an efficient distributed protocol for arranging nodes in mixnets that achieves low-latency properties while maintaining unbiasability against adversaries. Second, we introduce novel strategic routing schemes that optimize communication latency. Third, we design a load-balancing algorithm that evenly distributes traffic without undermining the latency-optimized characteristics of the routing strategies. Fourth, we conduct extensive evaluations using data from the deployed Nym mixnet, demonstrating substantial latency reductions with minimal anonymity loss across various mixnet designs—achieving up to 4x performance gains over state-of-the-art solutions. Finally, considering that latency reduction incurs either anonymity degradation or increased bandwidth overhead—as stated by the anonymity trilemma—we propose a cover-routing mechanism that enables clients to benefit from low-latency mixnets without compromising anonymity, at the modest cost of generating additional cover traffic."><meta itemprop="datePublished" content="February 27, 2026"><div class="page__inner-wrap"><header><h1 class="page__title" itemprop="headline">OptiMix: Scalable and Distributed Approaches for Latency Optimization in Modern Mixnets</h1><p>Published in <i>Network and Distributed System Security (NDSS) Symposium</i>, 2026</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 "OptiMix: Scalable and Distributed Approaches for Latency Optimization in Modern Mixnets," in NDSS 2026: 33rd Symposium on Network and Distributed System Security, Internet Society.<br /><a href="http://mmaahhddii1995.github.io/files/OptiMix.pdf">Download Paper</a> | <a href="http://mmaahhddii1995.github.io/files/OptiMix_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/OptiMix.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/OptiMix.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/OptiMix.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/OptiMix.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/DPMix.md" class="pagination--pager" title="DP-Mix: Differentially Private Routing in Mix Networks ">Previous</a> <a href="https://mmaahhddii1995.github.io/publication/WhenMixnetsFail.md" class="pagination--pager" title="When Mixnets Fail: Evaluating, Quantifying, and Mitigating the Impact of Adversarial Nodes in Mix Networks ">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>
