Files
rfc-index/waku/standards/application/54/x3dh-sessions.html
2025-12-22 15:08:29 +00:00

409 lines
40 KiB
HTML

<!DOCTYPE HTML>
<html lang="en" class="ayu" dir="ltr">
<head>
<!-- Book generated using mdBook -->
<meta charset="UTF-8">
<title>54/X3DH Sessions - Vac RFC</title>
<!-- Custom HTML head -->
<meta name="description" content="">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="theme-color" content="#ffffff">
<link rel="icon" href="../../../../favicon.svg">
<link rel="shortcut icon" href="../../../../favicon.png">
<link rel="stylesheet" href="../../../../css/variables.css">
<link rel="stylesheet" href="../../../../css/general.css">
<link rel="stylesheet" href="../../../../css/chrome.css">
<link rel="stylesheet" href="../../../../css/print.css" media="print">
<!-- Fonts -->
<link rel="stylesheet" href="../../../../FontAwesome/css/font-awesome.css">
<link rel="stylesheet" href="../../../../fonts/fonts.css">
<!-- Highlight.js Stylesheets -->
<link rel="stylesheet" href="../../../../highlight.css">
<link rel="stylesheet" href="../../../../tomorrow-night.css">
<link rel="stylesheet" href="../../../../ayu-highlight.css">
<!-- Custom theme stylesheets -->
<link rel="stylesheet" href="../../../../custom.css">
</head>
<body class="sidebar-visible no-js">
<div id="body-container">
<!-- Provide site root to javascript -->
<script>
var path_to_root = "../../../../";
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "ayu";
</script>
<!-- Work around some values being stored in localStorage wrapped in quotes -->
<script>
try {
var theme = localStorage.getItem('mdbook-theme');
var sidebar = localStorage.getItem('mdbook-sidebar');
if (theme.startsWith('"') && theme.endsWith('"')) {
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
}
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
}
} catch (e) { }
</script>
<!-- Set the theme before any content is loaded, prevents flash -->
<script>
var theme;
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
if (theme === null || theme === undefined) { theme = default_theme; }
var html = document.querySelector('html');
html.classList.remove('ayu')
html.classList.add(theme);
var body = document.querySelector('body');
body.classList.remove('no-js')
body.classList.add('js');
</script>
<input type="checkbox" id="sidebar-toggle-anchor" class="hidden">
<!-- Hide / unhide sidebar before it is displayed -->
<script>
var body = document.querySelector('body');
var sidebar = null;
var sidebar_toggle = document.getElementById("sidebar-toggle-anchor");
if (document.body.clientWidth >= 1080) {
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
sidebar = sidebar || 'visible';
} else {
sidebar = 'hidden';
}
sidebar_toggle.checked = sidebar === 'visible';
body.classList.remove('sidebar-visible');
body.classList.add("sidebar-" + sidebar);
</script>
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
<div class="sidebar-scrollbox">
<ol class="chapter"><li class="chapter-item expanded affix "><a href="../../../../index.html">Introduction</a></li><li class="chapter-item expanded "><a href="../../../../vac/index.html"><strong aria-hidden="true">1.</strong> Vac</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../vac/1/coss.html"><strong aria-hidden="true">1.1.</strong> 1/COSS</a></li><li class="chapter-item expanded "><a href="../../../../vac/2/mvds.html"><strong aria-hidden="true">1.2.</strong> 2/MVDS</a></li><li class="chapter-item expanded "><a href="../../../../vac/3/remote-log.html"><strong aria-hidden="true">1.3.</strong> 3/Remote Log</a></li><li class="chapter-item expanded "><a href="../../../../vac/4/mvds-meta.html"><strong aria-hidden="true">1.4.</strong> 4/MVDS Meta</a></li><li class="chapter-item expanded "><a href="../../../../vac/25/libp2p-dns-discovery.html"><strong aria-hidden="true">1.5.</strong> 25/Libp2p DNS Discovery</a></li><li class="chapter-item expanded "><a href="../../../../vac/32/rln-v1.html"><strong aria-hidden="true">1.6.</strong> 32/RLN-V1</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/index.html"><strong aria-hidden="true">1.7.</strong> Raw</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../vac/raw/consensus-hashgraphlike.html"><strong aria-hidden="true">1.7.1.</strong> Consensus Hashgraphlike</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/decentralized-messaging-ethereum.html"><strong aria-hidden="true">1.7.2.</strong> Decentralized Messaging Ethereum</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/eth-mls-offchain.html"><strong aria-hidden="true">1.7.3.</strong> ETH MLS Offchain</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/eth-mls-onchain.html"><strong aria-hidden="true">1.7.4.</strong> ETH MLS Onchain</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/deleted/eth-secpm.html"><strong aria-hidden="true">1.7.5.</strong> ETH SecPM</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/gossipsub-tor-push.html"><strong aria-hidden="true">1.7.6.</strong> Gossipsub Tor Push</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/logos-capability-discovery.html"><strong aria-hidden="true">1.7.7.</strong> Logos Capability Discovery</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/mix.html"><strong aria-hidden="true">1.7.8.</strong> Mix</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/noise-x3dh-double-ratchet.html"><strong aria-hidden="true">1.7.9.</strong> Noise X3DH Double Ratchet</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/rln-interep-spec.html"><strong aria-hidden="true">1.7.10.</strong> RLN Interep Spec</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/rln-stealth-commitments.html"><strong aria-hidden="true">1.7.11.</strong> RLN Stealth Commitments</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/rln-v2.html"><strong aria-hidden="true">1.7.12.</strong> RLN-V2</a></li><li class="chapter-item expanded "><a href="../../../../vac/raw/sds.html"><strong aria-hidden="true">1.7.13.</strong> SDS</a></li></ol></li><li class="chapter-item expanded "><a href="../../../../vac/template.html"><strong aria-hidden="true">1.8.</strong> Template</a></li></ol></li><li class="chapter-item expanded "><a href="../../../../waku/index.html"><strong aria-hidden="true">2.</strong> Waku</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../waku/standards/core/index.html"><strong aria-hidden="true">2.1.</strong> Standards - Core</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../waku/standards/core/10/waku2.html"><strong aria-hidden="true">2.1.1.</strong> 10/Waku2</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/11/relay.html"><strong aria-hidden="true">2.1.2.</strong> 11/Relay</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/12/filter.html"><strong aria-hidden="true">2.1.3.</strong> 12/Filter</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/13/store.html"><strong aria-hidden="true">2.1.4.</strong> 13/Store</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/14/message.html"><strong aria-hidden="true">2.1.5.</strong> 14/Message</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/15/bridge.html"><strong aria-hidden="true">2.1.6.</strong> 15/Bridge</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/17/rln-relay.html"><strong aria-hidden="true">2.1.7.</strong> 17/RLN Relay</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/19/lightpush.html"><strong aria-hidden="true">2.1.8.</strong> 19/Lightpush</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/31/enr.html"><strong aria-hidden="true">2.1.9.</strong> 31/ENR</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/33/discv5.html"><strong aria-hidden="true">2.1.10.</strong> 33/Discv5</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/34/peer-exchange.html"><strong aria-hidden="true">2.1.11.</strong> 34/Peer Exchange</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/36/bindings-api.html"><strong aria-hidden="true">2.1.12.</strong> 36/Bindings API</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/64/network.html"><strong aria-hidden="true">2.1.13.</strong> 64/Network</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/core/66/metadata.html"><strong aria-hidden="true">2.1.14.</strong> 66/Metadata</a></li></ol></li><li class="chapter-item expanded "><a href="../../../../waku/standards/application/index.html"><strong aria-hidden="true">2.2.</strong> Standards - Application</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../waku/standards/application/20/toy-eth-pm.html"><strong aria-hidden="true">2.2.1.</strong> 20/Toy ETH PM</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/application/26/payload.html"><strong aria-hidden="true">2.2.2.</strong> 26/Payload</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/application/53/x3dh.html"><strong aria-hidden="true">2.2.3.</strong> 53/X3DH</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/application/54/x3dh-sessions.html" class="active"><strong aria-hidden="true">2.2.4.</strong> 54/X3DH Sessions</a></li></ol></li><li class="chapter-item expanded "><a href="../../../../waku/standards/legacy/index.html"><strong aria-hidden="true">2.3.</strong> Standards - Legacy</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../waku/standards/legacy/6/waku1.html"><strong aria-hidden="true">2.3.1.</strong> 6/Waku1</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/legacy/7/data.html"><strong aria-hidden="true">2.3.2.</strong> 7/Data</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/legacy/8/mail.html"><strong aria-hidden="true">2.3.3.</strong> 8/Mail</a></li><li class="chapter-item expanded "><a href="../../../../waku/standards/legacy/9/rpc.html"><strong aria-hidden="true">2.3.4.</strong> 9/RPC</a></li></ol></li><li class="chapter-item expanded "><a href="../../../../waku/informational/index.html"><strong aria-hidden="true">2.4.</strong> Informational</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../waku/informational/22/toy-chat.html"><strong aria-hidden="true">2.4.1.</strong> 22/Toy Chat</a></li><li class="chapter-item expanded "><a href="../../../../waku/informational/23/topics.html"><strong aria-hidden="true">2.4.2.</strong> 23/Topics</a></li><li class="chapter-item expanded "><a href="../../../../waku/informational/27/peers.html"><strong aria-hidden="true">2.4.3.</strong> 27/Peers</a></li><li class="chapter-item expanded "><a href="../../../../waku/informational/29/config.html"><strong aria-hidden="true">2.4.4.</strong> 29/Config</a></li><li class="chapter-item expanded "><a href="../../../../waku/informational/30/adaptive-nodes.html"><strong aria-hidden="true">2.4.5.</strong> 30/Adaptive Nodes</a></li></ol></li><li class="chapter-item expanded "><a href="../../../../waku/deprecated/index.html"><strong aria-hidden="true">2.5.</strong> Deprecated</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../waku/deprecated/5/waku0.html"><strong aria-hidden="true">2.5.1.</strong> 5/Waku0</a></li><li class="chapter-item expanded "><a href="../../../../waku/deprecated/16/rpc.html"><strong aria-hidden="true">2.5.2.</strong> 16/RPC</a></li><li class="chapter-item expanded "><a href="../../../../waku/deprecated/18/swap.html"><strong aria-hidden="true">2.5.3.</strong> 18/Swap</a></li><li class="chapter-item expanded "><a href="../../../../waku/deprecated/fault-tolerant-store.html"><strong aria-hidden="true">2.5.4.</strong> Fault Tolerant Store</a></li></ol></li></ol></li><li class="chapter-item expanded "><a href="../../../../nomos/index.html"><strong aria-hidden="true">3.</strong> Nomos</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../nomos/raw/index.html"><strong aria-hidden="true">3.1.</strong> Raw</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../nomos/raw/nomosda-encoding.html"><strong aria-hidden="true">3.1.1.</strong> NomosDA Encoding</a></li><li class="chapter-item expanded "><a href="../../../../nomos/raw/nomosda-network.html"><strong aria-hidden="true">3.1.2.</strong> NomosDA Network</a></li><li class="chapter-item expanded "><a href="../../../../nomos/raw/p2p-hardware-requirements.html"><strong aria-hidden="true">3.1.3.</strong> P2P Hardware Requirements</a></li><li class="chapter-item expanded "><a href="../../../../nomos/raw/p2p-nat-solution.html"><strong aria-hidden="true">3.1.4.</strong> P2P NAT Solution</a></li><li class="chapter-item expanded "><a href="../../../../nomos/raw/p2p-network-bootstrapping.html"><strong aria-hidden="true">3.1.5.</strong> P2P Network Bootstrapping</a></li><li class="chapter-item expanded "><a href="../../../../nomos/raw/p2p-network.html"><strong aria-hidden="true">3.1.6.</strong> P2P Network</a></li><li class="chapter-item expanded "><a href="../../../../nomos/raw/sdp.html"><strong aria-hidden="true">3.1.7.</strong> SDP</a></li></ol></li><li class="chapter-item expanded "><a href="../../../../nomos/deprecated/index.html"><strong aria-hidden="true">3.2.</strong> Deprecated</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../nomos/deprecated/claro.html"><strong aria-hidden="true">3.2.1.</strong> Claro</a></li></ol></li></ol></li><li class="chapter-item expanded "><a href="../../../../codex/index.html"><strong aria-hidden="true">4.</strong> Codex</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../codex/raw/index.html"><strong aria-hidden="true">4.1.</strong> Raw</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../codex/raw/codex-block-exchange.html"><strong aria-hidden="true">4.1.1.</strong> Block Exchange</a></li><li class="chapter-item expanded "><a href="../../../../codex/raw/codex-marketplace.html"><strong aria-hidden="true">4.1.2.</strong> Marketplace</a></li></ol></li></ol></li><li class="chapter-item expanded "><a href="../../../../status/index.html"><strong aria-hidden="true">5.</strong> Status</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../status/24/curation.html"><strong aria-hidden="true">5.1.</strong> 24/Curation</a></li><li class="chapter-item expanded "><a href="../../../../status/28/featuring.html"><strong aria-hidden="true">5.2.</strong> 28/Featuring</a></li><li class="chapter-item expanded "><a href="../../../../status/55/1to1-chat.html"><strong aria-hidden="true">5.3.</strong> 55/1-to-1 Chat</a></li><li class="chapter-item expanded "><a href="../../../../status/56/communities.html"><strong aria-hidden="true">5.4.</strong> 56/Communities</a></li><li class="chapter-item expanded "><a href="../../../../status/61/community-history-service.html"><strong aria-hidden="true">5.5.</strong> 61/Community History Service</a></li><li class="chapter-item expanded "><a href="../../../../status/62/payloads.html"><strong aria-hidden="true">5.6.</strong> 62/Payloads</a></li><li class="chapter-item expanded "><a href="../../../../status/63/keycard-usage.html"><strong aria-hidden="true">5.7.</strong> 63/Keycard Usage</a></li><li class="chapter-item expanded "><a href="../../../../status/65/account-address.html"><strong aria-hidden="true">5.8.</strong> 65/Account Address</a></li><li class="chapter-item expanded "><a href="../../../../status/71/push-notification-server.html"><strong aria-hidden="true">5.9.</strong> 71/Push Notification Server</a></li><li class="chapter-item expanded "><a href="../../../../status/raw/index.html"><strong aria-hidden="true">5.10.</strong> Raw</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../status/raw/simple-scaling.html"><strong aria-hidden="true">5.10.1.</strong> Simple Scaling</a></li><li class="chapter-item expanded "><a href="../../../../status/raw/status-app-protocols.html"><strong aria-hidden="true">5.10.2.</strong> Status App Protocols</a></li><li class="chapter-item expanded "><a href="../../../../status/raw/status-mvds.html"><strong aria-hidden="true">5.10.3.</strong> Status MVDS</a></li><li class="chapter-item expanded "><a href="../../../../status/raw/url-data.html"><strong aria-hidden="true">5.10.4.</strong> URL Data</a></li><li class="chapter-item expanded "><a href="../../../../status/raw/url-scheme.html"><strong aria-hidden="true">5.10.5.</strong> URL Scheme</a></li></ol></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/index.html"><strong aria-hidden="true">5.11.</strong> Deprecated</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../../../status/deprecated/3rd-party.html"><strong aria-hidden="true">5.11.1.</strong> 3rd Party</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/account.html"><strong aria-hidden="true">5.11.2.</strong> Account</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/client.html"><strong aria-hidden="true">5.11.3.</strong> Client</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/dapp-browser-API-usage.html"><strong aria-hidden="true">5.11.4.</strong> Dapp Browser API Usage</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/eips.html"><strong aria-hidden="true">5.11.5.</strong> EIPs</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/ethereum-usage.html"><strong aria-hidden="true">5.11.6.</strong> Ethereum Usage</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/group-chat.html"><strong aria-hidden="true">5.11.7.</strong> Group Chat</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/IPFS-gateway-for-sticker-Pack.html"><strong aria-hidden="true">5.11.8.</strong> IPFS Gateway for Sticker Pack</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/keycard-usage-for-wallet-and-chat-keys.html"><strong aria-hidden="true">5.11.9.</strong> Keycard Usage for Wallet and Chat Keys</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/notifications.html"><strong aria-hidden="true">5.11.10.</strong> Notifications</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/payloads.html"><strong aria-hidden="true">5.11.11.</strong> Payloads</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/push-notification-server.html"><strong aria-hidden="true">5.11.12.</strong> Push Notification Server</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/secure-transport.html"><strong aria-hidden="true">5.11.13.</strong> Secure Transport</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/waku-mailserver.html"><strong aria-hidden="true">5.11.14.</strong> Waku Mailserver</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/waku-usage.html"><strong aria-hidden="true">5.11.15.</strong> Waku Usage</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/whisper-mailserver.html"><strong aria-hidden="true">5.11.16.</strong> Whisper Mailserver</a></li><li class="chapter-item expanded "><a href="../../../../status/deprecated/whisper-usage.html"><strong aria-hidden="true">5.11.17.</strong> Whisper Usage</a></li></ol></li></ol></li></ol>
</div>
<div id="sidebar-resize-handle" class="sidebar-resize-handle">
<div class="sidebar-resize-indicator"></div>
</div>
</nav>
<!-- Track and set sidebar scroll position -->
<script>
var sidebarScrollbox = document.querySelector('#sidebar .sidebar-scrollbox');
sidebarScrollbox.addEventListener('click', function(e) {
if (e.target.tagName === 'A') {
sessionStorage.setItem('sidebar-scroll', sidebarScrollbox.scrollTop);
}
}, { passive: true });
var sidebarScrollTop = sessionStorage.getItem('sidebar-scroll');
sessionStorage.removeItem('sidebar-scroll');
if (sidebarScrollTop) {
// preserve sidebar scroll position when navigating via links within sidebar
sidebarScrollbox.scrollTop = sidebarScrollTop;
} else {
// scroll sidebar to current active section when navigating via "next/previous chapter" buttons
var activeSection = document.querySelector('#sidebar .active');
if (activeSection) {
activeSection.scrollIntoView({ block: 'center' });
}
}
</script>
<div id="page-wrapper" class="page-wrapper">
<div class="page">
<div id="menu-bar-hover-placeholder"></div>
<div id="menu-bar" class="menu-bar sticky">
<div class="left-buttons">
<label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
<i class="fa fa-bars"></i>
</label>
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
<i class="fa fa-paint-brush"></i>
</button>
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
<li role="none"><button role="menuitem" class="theme" id="light">Light</button></li>
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
</ul>
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
<i class="fa fa-search"></i>
</button>
</div>
<h1 class="menu-title">Vac RFC</h1>
<div class="right-buttons">
<a href="../../../../print.html" title="Print this book" aria-label="Print this book">
<i id="print-button" class="fa fa-print"></i>
</a>
<a href="https://github.com/vacp2p/rfc-index" title="Git repository" aria-label="Git repository">
<i id="git-repository-button" class="fa fa-github"></i>
</a>
</div>
</div>
<div id="search-wrapper" class="hidden">
<form id="searchbar-outer" class="searchbar-outer">
<input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
</form>
<div id="searchresults-outer" class="searchresults-outer hidden">
<div id="searchresults-header" class="searchresults-header"></div>
<ul id="searchresults">
</ul>
</div>
</div>
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
<script>
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
});
</script>
<div id="content" class="content">
<main>
<h1 id="54waku2-x3dh-sessions"><a class="header" href="#54waku2-x3dh-sessions">54/WAKU2-X3DH-SESSIONS</a></h1>
<div class="table-wrapper"><table><thead><tr><th>Field</th><th>Value</th></tr></thead><tbody>
<tr><td>Name</td><td>Session management for Waku X3DH</td></tr>
<tr><td>Slug</td><td>54</td></tr>
<tr><td>Status</td><td>draft</td></tr>
<tr><td>Category</td><td>Standards Track</td></tr>
<tr><td>Editor</td><td>Aaryamann Challani <a href="mailto:p1ge0nh8er@proton.me">p1ge0nh8er@proton.me</a></td></tr>
<tr><td>Contributors</td><td>Andrea Piana <a href="mailto:andreap@status.im">andreap@status.im</a>, Pedro Pombeiro <a href="mailto:pedro@status.im">pedro@status.im</a>, Corey Petty <a href="mailto:corey@status.im">corey@status.im</a>, Oskar Thorén <a href="mailto:oskarth@titanproxy.com">oskarth@titanproxy.com</a>, Dean Eigenmann <a href="mailto:dean@status.im">dean@status.im</a>, Filip Dimitrijevic <a href="mailto:filip@status.im">filip@status.im</a></td></tr>
</tbody></table>
</div><!-- timeline:start -->
<h2 id="timeline"><a class="header" href="#timeline">Timeline</a></h2>
<ul>
<li><strong>2025-12-22</strong><a href="https://github.com/vacp2p/rfc-index/blob/0f1855edcf68ef982c4ce478b67d660809aa9830/docs/waku/standards/application/54/x3dh-sessions.md"><code>0f1855e</code></a> — Chore/fix headers (#239)</li>
<li><strong>2025-12-22</strong><a href="https://github.com/vacp2p/rfc-index/blob/b1a578393edf8487ccc97a5f25b25af9bf41efb3/docs/waku/standards/application/54/x3dh-sessions.md"><code>b1a5783</code></a> — Chore/mdbook updates (#237)</li>
<li><strong>2025-12-18</strong><a href="https://github.com/vacp2p/rfc-index/blob/d03e699084774ebecef9c6d4662498907c5e2080/docs/waku/standards/application/54/x3dh-sessions.md"><code>d03e699</code></a> — ci: add mdBook configuration (#233)</li>
<li><strong>2025-04-24</strong><a href="https://github.com/vacp2p/rfc-index/blob/db365cb756716fb76731c7988d41e9af9a850bc2/waku/standards/application/54/x3dh-sessions.md"><code>db365cb</code></a> — update waku/standards/application/54/x3dh-sessions.md (#151)</li>
<li><strong>2024-09-13</strong><a href="https://github.com/vacp2p/rfc-index/blob/3ab314d87d4525ff1296bf3d9ec634d570777b91/waku/standards/application/54/x3dh-sessions.md"><code>3ab314d</code></a> — Fix Files for Linting (#94)</li>
<li><strong>2024-08-05</strong><a href="https://github.com/vacp2p/rfc-index/blob/eb25cd06d679e94409072a96841de16a6b3910d5/waku/standards/application/54/x3dh-sessions.md"><code>eb25cd0</code></a> — chore: replace email addresses (#86)</li>
<li><strong>2024-03-21</strong><a href="https://github.com/vacp2p/rfc-index/blob/2eaa7949c4abe7d14e2b9560e8c045bf2e937c9a/waku/standards/application/54/x3dh-sessions.md"><code>2eaa794</code></a> — Broken Links + Change Editors (#26)</li>
<li><strong>2024-02-01</strong><a href="https://github.com/vacp2p/rfc-index/blob/0e490d46bb99c2fbae1ac193fbdfc11d84fb080d/waku/standards/application/54/x3dh-sessions.md"><code>0e490d4</code></a> — Rename X3DH-sessions.md to x3dh-sessions.md</li>
<li><strong>2024-01-31</strong><a href="https://github.com/vacp2p/rfc-index/blob/7f8b187f1b8b77af0c88c9fb154144494a7dfb7d/waku/standards/application/54/X3DH-sessions.md"><code>7f8b187</code></a> — Update and rename README.md to X3DH-sessions.md</li>
<li><strong>2024-01-27</strong><a href="https://github.com/vacp2p/rfc-index/blob/a22c2a0d79058ab435fcd38fe17a9f19021d5cd4/waku/standards/application/54/README.md"><code>a22c2a0</code></a> — Rename README.md to README.md</li>
<li><strong>2024-01-27</strong><a href="https://github.com/vacp2p/rfc-index/blob/eef961bfe3b1cf6aab66df5450555afd1d3543cb/waku/standards/application/56/README.md"><code>eef961b</code></a> — remove rfs folder</li>
<li><strong>2024-01-25</strong><a href="https://github.com/vacp2p/rfc-index/blob/484df92848f90025fc538c19616fff904d72bc26/waku/rfcs/standards/application/56/README.md"><code>484df92</code></a> — Create README.md</li>
</ul>
<!-- timeline:end -->
<h2 id="abstract"><a class="header" href="#abstract">Abstract</a></h2>
<p>This document specifies how to manage sessions based on an X3DH key exchange.
This includes how to establish new sessions,
how to re-establish them, how to maintain them, and how to close them.</p>
<p><a href="/waku/standards/application/53/x3dh.html">53/WAKU2-X3DH</a> specifies the Waku <code>X3DH</code> protocol
for end-to-end encryption.
Once two peers complete an X3DH handshake, they SHOULD establish an X3DH session.</p>
<h2 id="session-establishment"><a class="header" href="#session-establishment">Session Establishment</a></h2>
<p>A node identifies a peer by their <code>installation-id</code>
which MAY be interpreted as a device identifier.</p>
<h3 id="discovery-of-pre-key-bundles"><a class="header" href="#discovery-of-pre-key-bundles">Discovery of pre-key bundles</a></h3>
<p>The node's pre-key bundle MUST be broadcast on a content topic
derived from the node's public key, so that the first message may be PFS-encrypted.
Each peer MUST publish their pre-key bundle periodically to this topic,
otherwise they risk not being able to perform key-exchanges with other peers.
Each peer MAY publish to this topic when their metadata changes,
so that the other peer can update their local record.</p>
<p>If peer A wants to send a message to peer B,
it MUST derive the topic from peer B's public key, which has been shared out of band.
Partitioned topics have been used to balance privacy and
efficiency of broadcasting pre-key bundles.</p>
<p>The number of partitions that MUST be used is 5000.</p>
<p>The topic MUST be derived as follows:</p>
<pre><code class="language-js">var partitionsNum *big.Int = big.NewInt(5000)
var partition *big.Int = big.NewInt(0).Mod(peerBPublicKey, partitionsNum)
partitionTopic := "contact-discovery-" + strconv.FormatInt(partition.Int64(), 10)
var hash []byte = keccak256(partitionTopic)
var topicLen int = 4
if len(hash) &lt; topicLen {
topicLen = len(hash)
}
var contactCodeTopic [4]byte
for i = 0; i &lt; topicLen; i++ {
contactCodeTopic[i] = hash[i]
}
</code></pre>
<h3 id="initialization"><a class="header" href="#initialization">Initialization</a></h3>
<p>A node initializes a new session once a successful X3DH exchange has taken place.
Subsequent messages will use the established session until re-keying is necessary.</p>
<h3 id="negotiated-topic-to-be-used-for-the-session"><a class="header" href="#negotiated-topic-to-be-used-for-the-session">Negotiated topic to be used for the session</a></h3>
<p>After the peers have performed the initial key exchange,
they MUST derive a topic from their shared secret to send messages on.
To obtain this value, take the first four bytes of the keccak256 hash
of the shared secret encoded in hexadecimal format.</p>
<pre><code class="language-js">sharedKey, err := ecies.ImportECDSA(myPrivateKey).GenerateShared(
ecies.ImportECDSAPublic(theirPublicKey),
16,
16,
)
hexEncodedKey := hex.EncodeToString(sharedKey)
var hash []byte = keccak256(hexEncodedKey)
var topicLen int = 4
if len(hash) &lt; topicLen {
topicLen = len(hash)
}
var topic [4]byte
for i = 0; i &lt; topicLen; i++ {
topic[i] = hash[i]
}
</code></pre>
<p>To summarize,
following is the process for peer B to establish a session with peer A:</p>
<ol>
<li>Listen to peer B's Contact Code Topic to retrieve their bundle information,
including a list of active devices</li>
<li>Peer A sends their pre-key bundle on peer B's partitioned topic</li>
<li>Peer A and peer B perform the key-exchange using the shared pre-key bundles</li>
<li>The negotiated topic is derived from the shared secret</li>
<li>Peers A &amp; B exchange messages on the negotiated topic</li>
</ol>
<h3 id="concurrent-sessions"><a class="header" href="#concurrent-sessions">Concurrent sessions</a></h3>
<p>If a node creates two sessions concurrently between two peers,
the one with the symmetric key first in byte order SHOULD be used,
this marks that the other has expired.</p>
<h3 id="re-keying"><a class="header" href="#re-keying">Re-keying</a></h3>
<p>On receiving a bundle from a given peer with a higher version,
the old bundle SHOULD be marked as expired and
a new session SHOULD be established on the next message sent.</p>
<h3 id="multi-device-support"><a class="header" href="#multi-device-support">Multi-device support</a></h3>
<p>Multi-device support is quite challenging
as there is not a central place where information on which and how many devices
(identified by their respective <code>installation-id</code>) a peer has, is stored.</p>
<p>Furthermore, account recovery always needs to be taken into consideration,
where a user wipes clean the whole device and
the node loses all the information about any previous sessions.
Taking these considerations into account,
the way the network propagates multi-device information using X3DH bundles,
which will contain information about paired devices
as well as information about the sending device.
This means that every time a new device is paired,
the bundle needs to be updated and propagated with the new information,
the user has the responsibility to make sure the pairing is successful.</p>
<p>The method is loosely based on <a href="https://signal.org/docs/specifications/sesame/">Signal's Sesame Algorithm</a>.</p>
<h3 id="pairing"><a class="header" href="#pairing">Pairing</a></h3>
<p>A new <code>installation-id</code> MUST be generated on a per-device basis.
The device should be paired as soon as possible if other devices are present.</p>
<p>If a bundle is received, which has the same <code>IK</code> as the keypair present on the device,
the devices MAY be paired.
Once a user enables a new device,
a new bundle MUST be generated which includes pairing information.</p>
<p>The bundle MUST be propagated to contacts through the usual channels.</p>
<p>Removal of paired devices is a manual step that needs to be applied on each device,
and consist simply in disabling the device,
at which point pairing information will not be propagated anymore.</p>
<h3 id="sending-messages-to-a-paired-group"><a class="header" href="#sending-messages-to-a-paired-group">Sending messages to a paired group</a></h3>
<p>When sending a message,
the peer SHOULD send a message to other <code>installation-id</code> that they have seen.
The node caps the number of devices to <code>n</code>, ordered by last activity.
The node sends messages using pairwise encryption, including their own devices.</p>
<p>Where <code>n</code> is the maximum number of devices that can be paired.</p>
<h3 id="account-recovery"><a class="header" href="#account-recovery">Account recovery</a></h3>
<p>Account recovery is the same as adding a new device,
and it MUST be handled the same way.</p>
<h3 id="partitioned-devices"><a class="header" href="#partitioned-devices">Partitioned devices</a></h3>
<p>In some cases
(i.e. account recovery when no other pairing device is available, device not paired),
it is possible that a device will receive a message
that is not targeted to its own <code>installation-id</code>.
In this case an empty message containing bundle information MUST be sent back,
which will notify the receiving end not to include the device in any further communication.</p>
<h2 id="security-considerations"><a class="header" href="#security-considerations">Security Considerations</a></h2>
<ol>
<li>Inherits all security considerations from <a href="/waku/standards/application/53/x3dh.html">53/WAKU2-X3DH</a>.</li>
</ol>
<h3 id="recommendations"><a class="header" href="#recommendations">Recommendations</a></h3>
<ol>
<li>The value of <code>n</code> SHOULD be configured by the app-protocol.
<ul>
<li>The default value SHOULD be 3,
since a larger number of devices will result in a larger bundle size,
which may not be desirable in a peer-to-peer network.</li>
</ul>
</li>
</ol>
<h2 id="copyright"><a class="header" href="#copyright">Copyright</a></h2>
<p>Copyright and related rights waived via
<a href="https://creativecommons.org/publicdomain/zero/1.0/">CC0</a>.</p>
<h2 id="references"><a class="header" href="#references">References</a></h2>
<ul>
<li><a href="/waku/standards/application/53/x3dh.html">53/WAKU2-X3DH</a></li>
<li><a href="https://signal.org/docs/specifications/sesame/">Signal's Sesame Algorithm</a></li>
</ul>
</main>
<nav class="nav-wrapper" aria-label="Page navigation">
<!-- Mobile navigation buttons -->
<a rel="prev" href="../../../../waku/standards/application/53/x3dh.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
<i class="fa fa-angle-left"></i>
</a>
<a rel="next prefetch" href="../../../../waku/standards/legacy/index.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
<i class="fa fa-angle-right"></i>
</a>
<div style="clear: both"></div>
</nav>
</div>
</div>
<nav class="nav-wide-wrapper" aria-label="Page navigation">
<a rel="prev" href="../../../../waku/standards/application/53/x3dh.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
<i class="fa fa-angle-left"></i>
</a>
<a rel="next prefetch" href="../../../../waku/standards/legacy/index.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
<i class="fa fa-angle-right"></i>
</a>
</nav>
</div>
<script>
window.playground_copyable = true;
</script>
<script src="../../../../elasticlunr.min.js"></script>
<script src="../../../../mark.min.js"></script>
<script src="../../../../searcher.js"></script>
<script src="../../../../clipboard.min.js"></script>
<script src="../../../../highlight.js"></script>
<script src="../../../../book.js"></script>
<!-- Custom JS scripts -->
<script src="../../../../scripts/rfc-index.js"></script>
</div>
</body>
</html>