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<!DOCTYPE html> <html lang="en"><head><title>Focus on Security and Comprehensive Privacy Protection – Threema</title><link rel="canonical" href="https://threema.ch/en/security"/> <link rel="stylesheet" href="https://static.threema.ch/fonts/labgrotesque.css"/> <meta name="viewport" content="width=device-width, initial-scale=1.0"/> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <meta name="description" content="Security, confidentiality, and metadata restraint lie at the heart of Threema, the messenger for individuals and companies."/> <meta name="apple-itunes-app" content="app-id=578665578, affiliate-data=10lJMu"/> <meta name="google-play-app" content="app-id=ch.threema.app"/> <meta property="og:image" content="https://threema.ch/images/logo-big.png"/> <meta property="og:image:secure_url" content="https://threema.ch/images/logo-big.png"/> <meta name="twitter:card" content="summary"/> <meta name="twitter:site" content="@ThreemaApp"/> <meta property="og:title" 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class="navbar-toggler collapsed" type="button" data-toggle="collapse" data-target=".navbar-collapse"><span class="navbar-toggler-icon"></span></button><div class="nav-top"><div class="navbar-top-subNav d-sm-inline-flex flex-sm-row-reverse"><ul class="navbar-nav ml-auto"><li class="nav-item thr-jobs" data-key="jobs"><a class="nav-link" href="/en/jobs"><span class="nav-link-text">Jobs<div class="nav-link-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10"><path d="M7.19 8.14H2.42v1.33h7.06V2.42H8.15v4.79L1.46.53l-.94.94 6.67 6.67Z" fill="currentColor" /></svg> </div></span></a></li></ul></div><div class="nav-lang nav-dropdown dropdown"><div class="nav-dropdown-btn nav-dropdown-btn--lang thr-textIcon thr-textIcon--small" data-toggle="dropdown"><div class="thr-svg thr-svg--w-100 d-flex w-3"><svg xmlns="http://www.w3.org/2000/svg" xml:space="preserve" viewBox="0 0 13.3 13.3"><path fill="none" d="M-8.8-10.3h71.9c.9 0 1.2.1 1.5.3s.6.4.8.8c.2.3.3.6.3 1.5v28.9c0 .9-.1 1.2-.3 1.5-.2.3-.4.6-.8.8-.3.2-.6.3-1.5.3H-8.8c-.9 0-1.2-.1-1.5-.3-.3-.2-.6-.4-.8-.8-.2-.3-.3-.6-.3-1.5v-29c0-.9.1-1.2.3-1.5s.4-.6.8-.8.6-.2 1.5-.2z"/><path fill="currentColor" d="M6.7 0a6.7 6.7 0 1 0 0 13.4A6.7 6.7 0 0 0 6.7 0zm4.6 4h-2c-.2-.8-.5-1.6-.9-2.4 1.2.5 2.2 1.3 2.9 2.4zM6.7 1.4c.6.8 1 1.7 1.3 2.6H5.4c.3-.9.7-1.8 1.3-2.6zM1.5 8c-.1-.4-.2-.9-.2-1.3s.1-.9.2-1.3h2.3c-.1.4-.1.8-.1 1.3s0 .9.1 1.3H1.5zm.6 1.3h2c.2.8.5 1.6.9 2.4-1.3-.4-2.3-1.3-2.9-2.4zM4 4H2c.6-1.1 1.7-2 2.9-2.4-.4.8-.7 1.6-.9 2.4zm2.7 8c-.6-.8-1-1.7-1.3-2.6h2.5c-.2.9-.7 1.8-1.2 2.6zm1.5-4H5.1c0-.4-.1-.9-.1-1.3 0-.5 0-.9.1-1.3h3.1c.1.4.1.9.1 1.3s0 .9-.1 1.3zm.2 3.7c.4-.7.7-1.5.9-2.4h2c-.7 1.1-1.7 2-2.9 2.4zM9.6 8c.1-.4.1-.9.1-1.3 0-.5 0-.9-.1-1.3h2.3c0 .4.1.8.1 1.3s-.1.9-.2 1.3H9.6z"/></svg> </div>en</div><div class="nav-dropdown-menu dropdown-menu"><a class="nav-dropdown-item nav-dropdown-item--small text-left" href="/de/security" dir="ltr"><span class="nav-dropdown-itemTitle nav-dropdown-itemTitle--small">Deutsch</span></a><a class="nav-dropdown-item nav-dropdown-item--small text-left nav-dropdown-item--active" href="/en/security" dir="ltr"><span class="nav-dropdown-itemTitle nav-dropdown-itemTitle--small">English</span></a><a class="nav-dropdown-item nav-dropdown-item--small text-left" href="/fr/security" dir="ltr"><span class="nav-dropdown-itemTitle nav-dropdown-itemTitle--small">Français</span></a><a class="nav-dropdown-item nav-dropdown-item--small text-left" href="/es/security" dir="ltr"><span class="nav-dropdown-itemTitle nav-dropdown-itemTitle--small">Español</span></a></div></div><div class="nav-dropdown dropdown"><button class="thr-btn-transparent nav-dropdown-btn nav-dropdown-btn--products dropdown-toggle thr-textIcon thr-textIcon--right thr-textIcon--chevronDown" data-toggle="dropdown">Products</button><div class="nav-dropdown-menu dropdown-menu"><div class="nav-dropdown-group text-left" dir="ltr"><a class="nav-dropdown-item nav-dropdown-item--center" href="/en"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"></div><div><span class="nav-dropdown-itemTitle">Overview</span></div></a></div><div class="nav-dropdown-group text-left" dir="ltr"><p class="nav-dropdown-group-title">For Individuals</p><a class="nav-dropdown-item nav-dropdown-item--active" href="/en/secure-messenger"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 61 60"><g fill="none" fill-rule="nonzero" transform="translate(.5)"><rect width="60" height="60" fill="#323232" rx="2.93"/><path fill="#FFF" d="m21.552 40.359-9.657 2.414 2.063-8.255c-2.044-2.693-3.235-5.93-3.235-9.41 0-9.369 8.63-16.963 19.277-16.963s19.277 7.594 19.277 16.962c0 9.369-8.63 16.963-19.277 16.963-3.03 0-5.897-.615-8.448-1.711Zm2.98-16.66h-.216a.879.879 0 0 0-.878.88v7.706c0 .486.393.88.878.88h11.368a.879.879 0 0 0 .879-.88v-7.707a.879.879 0 0 0-.88-.879h-.214v-2.184a5.466 5.466 0 0 0-5.472-5.46 5.465 5.465 0 0 0-5.466 5.46V23.7Zm8.75 0h-6.563v-2.183a3.28 3.28 0 0 1 3.28-3.277 3.28 3.28 0 0 1 3.282 3.277v2.183Z"/><path fill="#05A63F" d="M33.278 49.687a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm-11.833 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm23.666 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Z"/></g></svg> </div><div><span class="nav-dropdown-itemTitle">Threema</span><span class="nav-dropdown-itemDesc">For individuals</span></div></a><a class="nav-dropdown-item " href="/en/gateway"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"></div><div><span class="nav-dropdown-itemTitle">Threema Gateway</span><span class="nav-dropdown-itemDesc">Integration into your software</span></div></a></div><div class="nav-dropdown-group text-left" dir="ltr"><p class="nav-dropdown-group-title">For Companies</p><a class="nav-dropdown-item " href="/en/work/business-messenger?li=business-solution"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 60 60"><g fill="none" fill-rule="evenodd"><rect width="60" height="60" fill="#004A7F" rx="3"/><path fill="#FFF" fill-rule="nonzero" d="m21.552 40.359-9.657 2.414 2.063-8.255c-2.044-2.693-3.235-5.93-3.235-9.41 0-9.369 8.63-16.963 19.277-16.963s19.277 7.594 19.277 16.962c0 9.369-8.63 16.963-19.277 16.963-3.03 0-5.897-.615-8.448-1.711Zm2.98-16.66h-.216a.879.879 0 0 0-.878.88v7.706c0 .486.393.88.878.88h11.368a.879.879 0 0 0 .879-.88v-7.707a.879.879 0 0 0-.88-.879h-.214v-2.184a5.466 5.466 0 0 0-5.472-5.46 5.465 5.465 0 0 0-5.466 5.46V23.7Zm8.75 0h-6.563v-2.183a3.28 3.28 0 0 1 3.28-3.277 3.28 3.28 0 0 1 3.282 3.277v2.183Z"/><path fill="#0096FF" d="M33.278 49.687a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm-11.833 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm23.666 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Z"/></g></svg> </div><div><span class="nav-dropdown-itemTitle">Threema Work</span><span class="nav-dropdown-itemDesc">For companies</span></div></a><a class="nav-dropdown-item " href="/en/broadcast"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"></div><div><span class="nav-dropdown-itemTitle">Threema Broadcast</span><span class="nav-dropdown-itemDesc">Top-down communication</span></div></a><a class="nav-dropdown-item " href="/en/onprem"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><g fill="none" fill-rule="evenodd"><path fill="#BB2E27" d="M4.883 0A4.883 4.883 0 0 0 0 4.883v90.234A4.883 4.883 0 0 0 4.883 100h90.234A4.883 4.883 0 0 0 100 95.117V4.883A4.883 4.883 0 0 0 95.117 0H4.883Z"/><g fill="#FFF"><path d="m36.975 66.842-15.548 4.147 3.323-14.183c-3.29-4.627-5.21-10.187-5.21-16.168 0-16.095 13.896-29.144 31.035-29.144 17.14 0 31.034 13.049 31.034 29.144S67.715 69.782 50.575 69.782c-4.878 0-9.493-1.057-13.6-2.94Zm4.796-28.623h-.347c-.78 0-1.414.676-1.414 1.511v13.24c0 .834.633 1.51 1.414 1.51h18.301c.781 0 1.414-.676 1.414-1.51V39.73c0-.835-.633-1.51-1.414-1.51h-.345v-3.754c0-5.175-3.94-9.38-8.809-9.38-4.86 0-8.8 4.205-8.8 9.38v3.753Zm14.087 0H45.293v-3.751c0-3.107 2.364-5.631 5.28-5.631 2.921 0 5.285 2.524 5.285 5.63v3.752ZM55.853 82.51a5.278 5.278 0 0 1-5.283 5.281 5.28 5.28 0 1 1 5.283-5.28m-19.05 0a5.28 5.28 0 0 1-5.283 5.28 5.28 5.28 0 1 1 5.283-5.28m38.1 0a5.278 5.278 0 0 1-5.284 5.28 5.277 5.277 0 0 1-5.276-5.28 5.28 5.28 0 0 1 10.56 0"/></g></g></svg> </div><div><span class="nav-dropdown-itemTitle">Threema OnPrem</span><span class="nav-dropdown-itemDesc">Self-hosted enterprise messaging</span></div></a><a class="nav-dropdown-item " href="/en/gateway"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"></div><div><span class="nav-dropdown-itemTitle">Threema Gateway</span><span class="nav-dropdown-itemDesc">Integration into your software</span></div></a></div></div></div></div><div class="navbar-collapse collapse d-sm-inline-flex flex-sm-row-reverse"><div class="navbar-collapse-top"><div class="thr-headLogoWrapper"><a class="thr-headBrandIcon" href="/en/secure-messenger"><img alt="Threema" class="thr-headBrandIcon__img" src="/images/icons/threema-icon.svg"/></a><a class="navbar-brand" href="/en/secure-messenger"><img alt="Threema." class="thr-logo" src="/images/logo.svg"/></a></div><button type="button" class="navbar-toggler collapsed navbar-close-btn" data-toggle="collapse" data-target=".navbar-collapse"><div class=""></div></button></div><ul class="navbar-nav"><li class="nav-item thr-security active" data-key="security"><a class="nav-link" href="/en/security"><span class="nav-link-text">Security<div class="nav-link-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10"><path d="M7.19 8.14H2.42v1.33h7.06V2.42H8.15v4.79L1.46.53l-.94.94 6.67 6.67Z" fill="currentColor" /></svg> </div></span></a></li><li class="nav-item thr-downloads" data-key="downloads"><a class="nav-link" href="/en/download"><span class="nav-link-text">Download<div class="nav-link-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10"><path d="M7.19 8.14H2.42v1.33h7.06V2.42H8.15v4.79L1.46.53l-.94.94 6.67 6.67Z" fill="currentColor" /></svg> </div></span></a></li><li class="nav-item thr-about nav-item--withSubNav" data-key="about"><button class="nav-link">About</button></li><li class="nav-item thr-support" data-key="support"><a class="nav-link" href="/en/support"><span class="nav-link-text">Support<div class="nav-link-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10"><path d="M7.19 8.14H2.42v1.33h7.06V2.42H8.15v4.79L1.46.53l-.94.94 6.67 6.67Z" fill="currentColor" /></svg> </div></span></a></li><li class="nav-item thr-blog" data-key="blog"><a class="nav-link" href="/en/blog"><span class="nav-link-text">Blog<div class="nav-link-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10"><path d="M7.19 8.14H2.42v1.33h7.06V2.42H8.15v4.79L1.46.53l-.94.94 6.67 6.67Z" fill="currentColor" 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1.3h2c.2.8.5 1.6.9 2.4-1.3-.4-2.3-1.3-2.9-2.4zM4 4H2c.6-1.1 1.7-2 2.9-2.4-.4.8-.7 1.6-.9 2.4zm2.7 8c-.6-.8-1-1.7-1.3-2.6h2.5c-.2.9-.7 1.8-1.2 2.6zm1.5-4H5.1c0-.4-.1-.9-.1-1.3 0-.5 0-.9.1-1.3h3.1c.1.4.1.9.1 1.3s0 .9-.1 1.3zm.2 3.7c.4-.7.7-1.5.9-2.4h2c-.7 1.1-1.7 2-2.9 2.4zM9.6 8c.1-.4.1-.9.1-1.3 0-.5 0-.9-.1-1.3h2.3c0 .4.1.8.1 1.3s-.1.9-.2 1.3H9.6z"/></svg> </div>English</div></div><div class="nav-actions nav-actions--sm"><a class="nav-actions-item thr-btn thr-btn--big thr-btn--primary50 thr-btn--brand-primary" href="/en/work/business-messenger">Threema for organizations</a></div></ul><div class="nav-actions"><a class="nav-actions-item thr-btn thr-btn--primary50 thr-btn--small thr-btn--brand-primary" href="/en/work/business-messenger">Threema for organizations</a></div><div class="navbar-bottom"><div class="nav-item nav-item--button thr-btn-transparent thr-btn--big nav-item--showOnlyMobile nav-item--withSubNav " data-key="products"><div class="nav-link" title="Products">Products</div></div></div></div></div></nav><div class="nav-subNav navbar-expand-md text-left" dir="ltr"><div class="container-fluid container-fluid--xl"><button type="button" class="nav-subNav-close" data-toggle="collapse"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path fill="currentColor" fill-rule="evenodd" d="m6.843 13.015 5.056 5.056-1.414 1.414L3 12l7.485-7.485 1.414 1.414-5.085 5.086H21v2z"/></svg> Back</button><div class="navbar-subNav navbar-nav" data-key="about"><div class="navbar-subNav-inner col-lg-3"><ul class="navbar-subNav-grid subNav-col-1"><div class="navbar-subNav-triangle d-none d-lg-block"></div><ul class="subNav-col" dir=""><li class="nav-item thr-about_s1 nav-item--subNav nav-item--withSubNav" data-key="about_s1"><span class="nav-link subNav-heading"><span class="subNav-heading-icon"><?xml version="1.0" encoding="UTF-8"?> <svg width="64px" height="64px" viewBox="0 0 64 64" version="1.1" xmlns="http://www.w3.org/2000/svg" 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thr-about_s1_press nav-item--subSubNav" data-key="about_s1_press"><a class="nav-link" href="/en/press"><span class="nav-link-text">Press<div class="nav-link-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10"><path d="M7.19 8.14H2.42v1.33h7.06V2.42H8.15v4.79L1.46.53l-.94.94 6.67 6.67Z" fill="currentColor" /></svg> </div></span></a></li></ul></li></ul></ul></div></div><ul class="navbar-subNav navbar-nav py-2" data-key="products"><ul class="subNav-col py-2"><li class="nav-item nav-item--subNav nav-item--withSubNav"><ul class="subNav-items p-0"><li class="nav-item"><a class="nav-dropdown-item nav-dropdown-item--center" href="/en"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"></div><div><span class="nav-dropdown-itemTitle">Overview</span></div></a></li></ul></li></ul><ul class="subNav-col py-2"><li class="nav-item nav-item--subNav nav-item--withSubNav"><p class="nav-dropdown-group-title">For Individuals</p><ul class="subNav-items p-0"><li class="nav-item active"><a class="nav-dropdown-item" href="/en/secure-messenger"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 61 60"><g fill="none" fill-rule="nonzero" transform="translate(.5)"><rect width="60" height="60" fill="#323232" rx="2.93"/><path fill="#FFF" d="m21.552 40.359-9.657 2.414 2.063-8.255c-2.044-2.693-3.235-5.93-3.235-9.41 0-9.369 8.63-16.963 19.277-16.963s19.277 7.594 19.277 16.962c0 9.369-8.63 16.963-19.277 16.963-3.03 0-5.897-.615-8.448-1.711Zm2.98-16.66h-.216a.879.879 0 0 0-.878.88v7.706c0 .486.393.88.878.88h11.368a.879.879 0 0 0 .879-.88v-7.707a.879.879 0 0 0-.88-.879h-.214v-2.184a5.466 5.466 0 0 0-5.472-5.46 5.465 5.465 0 0 0-5.466 5.46V23.7Zm8.75 0h-6.563v-2.183a3.28 3.28 0 0 1 3.28-3.277 3.28 3.28 0 0 1 3.282 3.277v2.183Z"/><path fill="#05A63F" d="M33.278 49.687a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm-11.833 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm23.666 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Z"/></g></svg> </div><div><span class="nav-dropdown-itemTitle">Threema</span><span class="nav-dropdown-itemDesc">For individuals</span></div></a></li><li class="nav-item"><a class="nav-dropdown-item" href="/en/gateway"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"></div><div><span class="nav-dropdown-itemTitle">Threema Gateway</span><span class="nav-dropdown-itemDesc">Integration into your software</span></div></a></li></ul></li></ul><ul class="subNav-col py-2"><li class="nav-item nav-item--subNav nav-item--withSubNav"><p class="nav-dropdown-group-title">For Companies</p><ul class="subNav-items p-0"><li class="nav-item"><a class="nav-dropdown-item" href="/en/work/business-messenger?li=business-solution"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 60 60"><g fill="none" fill-rule="evenodd"><rect width="60" height="60" fill="#004A7F" rx="3"/><path fill="#FFF" fill-rule="nonzero" d="m21.552 40.359-9.657 2.414 2.063-8.255c-2.044-2.693-3.235-5.93-3.235-9.41 0-9.369 8.63-16.963 19.277-16.963s19.277 7.594 19.277 16.962c0 9.369-8.63 16.963-19.277 16.963-3.03 0-5.897-.615-8.448-1.711Zm2.98-16.66h-.216a.879.879 0 0 0-.878.88v7.706c0 .486.393.88.878.88h11.368a.879.879 0 0 0 .879-.88v-7.707a.879.879 0 0 0-.88-.879h-.214v-2.184a5.466 5.466 0 0 0-5.472-5.46 5.465 5.465 0 0 0-5.466 5.46V23.7Zm8.75 0h-6.563v-2.183a3.28 3.28 0 0 1 3.28-3.277 3.28 3.28 0 0 1 3.282 3.277v2.183Z"/><path fill="#0096FF" d="M33.278 49.687a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm-11.833 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm23.666 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Z"/></g></svg> </div><div><span class="nav-dropdown-itemTitle">Threema Work</span><span class="nav-dropdown-itemDesc">For companies</span></div></a></li><li class="nav-item"><a class="nav-dropdown-item" href="/en/broadcast"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"></div><div><span class="nav-dropdown-itemTitle">Threema Broadcast</span><span class="nav-dropdown-itemDesc">Top-down communication</span></div></a></li><li class="nav-item"><a class="nav-dropdown-item" href="/en/onprem"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><g fill="none" fill-rule="evenodd"><path fill="#BB2E27" d="M4.883 0A4.883 4.883 0 0 0 0 4.883v90.234A4.883 4.883 0 0 0 4.883 100h90.234A4.883 4.883 0 0 0 100 95.117V4.883A4.883 4.883 0 0 0 95.117 0H4.883Z"/><g fill="#FFF"><path d="m36.975 66.842-15.548 4.147 3.323-14.183c-3.29-4.627-5.21-10.187-5.21-16.168 0-16.095 13.896-29.144 31.035-29.144 17.14 0 31.034 13.049 31.034 29.144S67.715 69.782 50.575 69.782c-4.878 0-9.493-1.057-13.6-2.94Zm4.796-28.623h-.347c-.78 0-1.414.676-1.414 1.511v13.24c0 .834.633 1.51 1.414 1.51h18.301c.781 0 1.414-.676 1.414-1.51V39.73c0-.835-.633-1.51-1.414-1.51h-.345v-3.754c0-5.175-3.94-9.38-8.809-9.38-4.86 0-8.8 4.205-8.8 9.38v3.753Zm14.087 0H45.293v-3.751c0-3.107 2.364-5.631 5.28-5.631 2.921 0 5.285 2.524 5.285 5.63v3.752ZM55.853 82.51a5.278 5.278 0 0 1-5.283 5.281 5.28 5.28 0 1 1 5.283-5.28m-19.05 0a5.28 5.28 0 0 1-5.283 5.28 5.28 5.28 0 1 1 5.283-5.28m38.1 0a5.278 5.278 0 0 1-5.284 5.28 5.277 5.277 0 0 1-5.276-5.28 5.28 5.28 0 0 1 10.56 0"/></g></g></svg> </div><div><span class="nav-dropdown-itemTitle">Threema OnPrem</span><span class="nav-dropdown-itemDesc">Self-hosted enterprise messaging</span></div></a></li><li class="nav-item"><a class="nav-dropdown-item" href="/en/gateway"><div class="nav-dropdown-itemIcon thr-svg thr-svg--w-100"></div><div><span class="nav-dropdown-itemTitle">Threema Gateway</span><span class="nav-dropdown-itemDesc">Integration into your software</span></div></a></li></ul></li></ul></ul><ul class="navbar-subNav navbar-nav" data-key="logins"><li class="nav-item thr-work-login nav-item--subNav" data-key="work-login"><a class="nav-link" href="https://work.threema.ch/en/login"><span class="nav-link-text">Threema Work<div class="nav-link-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10"><path d="M7.19 8.14H2.42v1.33h7.06V2.42H8.15v4.79L1.46.53l-.94.94 6.67 6.67Z" fill="currentColor" /></svg> </div></span></a></li><li class="nav-item thr-broadcast-login nav-item--subNav" data-key="broadcast-login"><a class="nav-link" href="https://broadcast.threema.ch/en/login"><span class="nav-link-text">Threema Broadcast<div class="nav-link-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10"><path d="M7.19 8.14H2.42v1.33h7.06V2.42H8.15v4.79L1.46.53l-.94.94 6.67 6.67Z" fill="currentColor" /></svg> </div></span></a></li><li class="nav-item thr-gateway-login nav-item--subNav" data-key="gateway-login"><a class="nav-link" href="https://gateway.threema.ch/en/login"><span class="nav-link-text">Threema Gateway<div class="nav-link-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10"><path d="M7.19 8.14H2.42v1.33h7.06V2.42H8.15v4.79L1.46.53l-.94.94 6.67 6.67Z" fill="currentColor" /></svg> </div></span></a></li></ul><ul class="navbar-subNav navbar-nav" data-key="language"><div class="nav-item" data-key="products"><a class="nav-link" href="/de/security" title="Deutsch">Deutsch</a></div><div class="nav-item active" data-key="products"><a class="nav-link" href="/en/security" title="English">English</a></div><div class="nav-item" data-key="products"><a class="nav-link" href="/fr/security" title="Français">Français</a></div><div class="nav-item" data-key="products"><a class="nav-link" href="/es/security" title="Español">Español</a></div></ul></div></div></header><main class="main" role="main"><div class="thr-teaserBanner"><div class="container-fluid"><div class="thr-teaserBanner__inner"><p class="thr-teaserBanner__text position-relative pr-4 pr-md-0"><b>Privacy Checkup:</b> Find out how to improve your online privacy<a class="d-md-none position-absolute left-0 top-0 right-0 bottom-0 thr-textIcon thr-textIcon--right thr-textIcon--chevronRightWhite justify-content-end" href="/en/blog/posts/privacy-checkup"></a></p><a href="/en/blog/posts/privacy-checkup" class="thr-teaserBanner__button thr-btn-secondary thr-btn-secondary--white thr-btn-secondary--xsmall d-none d-md-block">Learn more</a></div></div></div><div class="thr-section thr-security-title-section"> <div class="container-fluid"> <div class="row justify-content-center"> <div class="col-lg-12 col-md-10 col-12"> <h1 class="text-center">Threema Focuses on Security and Comprehensive Privacy Protection</h1> <div class="thr-bar-divider mx-auto"></div> </div> <div class="col-md-8 col-10"> <h4 class="text-center text-secondary-gray600 ">Security, confidentiality, and metadata restraint lie at the heart of Threema.</h4> </div> </div> </div> </div> <div class="thr-section thr-security-privacy-section"> <div class="container-fluid"> <div class="row justify-content-center"> <div class="col-10"> <h1>Security and Privacy by Design</h1> <div class="text-secondary-gray600"> <p>Threema was designed from the ground up with security and privacy in mind. Since day one, the restraint on metadata has been our guiding principle. For where there is no data, no data can be misused. Threema’s server only assumes the role of a switch: After a message has been delivered to its recipient, it will be permanently deleted at once.</p><p>The focus on security and privacy protection is also reflected in the implementation of numerous individual features, such as <a href="/en/blog/posts/profile-pictures">profile pictures</a>, <a href="/en/blog/posts/threema-calls">Threema calls</a>, and the <a href="/en/blog/posts/threema-for-desktop">desktop app / web client</a>.</p><p>Threema is committed to full transparency, and for this reason, the apps are <a href="/en/open-source">open source</a>. On top of that, renowned experts are regularly commissioned to conduct comprehensive security audits:</p> </div> <a href="/en/faq/code_audit" class="thr-btn-secondary">Security audits</a> <div class="text-secondary-gray600 mt-4"> <p>How does Threema stack up against Signal, Telegram, and WhatsApp? Find out:</p> </div> <a href="/en/messenger-comparison" class="thr-btn-secondary">Messenger comparison</a> </div> </div> </div> </div> </div> <div class="thr-section thr-security-endtoend-section"> <div class="container-fluid"> <div class="row justify-content-center justify-content-md-start"> <div class="col-lg-6 offset-md-1 offset-lg-0 order-lg-2 col-md-10 col-12 thr-img-col"> <div class="thr-img-top"> <div class="avatar-chat-bubble"> <div class="acb-avatar"> <div class="thr-avatar-element" thr-avatar-group="security-1" thr-avatar-style="gray"></div> </div> <div class="acb-message"> <div class="acb-m-arrow"></div> <div class="acb-m-content"> <div class="thr-chat-animation thr-ca-decrypt-text" thr-play-in-view thr-id="eemsg1"> I have news about the YLO project… Could you send me the current report, please? Thank you! </div> </div> </div> </div> </div> <div class="thr-img-bottom"> <div class="avatar-chat-bubble r"> <div class="acb-avatar"> <div class="thr-avatar-element" thr-avatar-group="security-1" thr-avatar-style="gray"></div> </div> <div class="acb-message"> <div class="acb-m-arrow"></div> <div class="acb-m-content"> <div class="thr-chat-animation thr-ca-decrypt-text" thr-play-after="eemsg1" thr-id="eemsg2"> Sure, I’ll send it right away… I’m curious about your YLO news! :-) </div> </div> </div> </div> </div> </div> <div class="offset-md-1 offset-lg-0 col-lg-6 col-md-8 col-10 thr-desc-col"> <span class="sp-pub-i-LockE2E thr-sprite-icon"></span> <div class="thr-bar-divider"></div> <h1 class="thr-section-title">Consistent End-to-End Encryption</h1> <p>Threema employs the tried and tested open-source cryptography library NaCl. All messages are end-to-end encrypted, and the users are in control of the key exchange. This guarantees that no third party, not even the server operator, can decrypt messages.<br/><br/>The whole communication – including group messages, photos and videos, files, calls, and even status messages – is always end-to-end encrypted. In contrast to conventional messenger apps, a fallback to unencrypted connections is ruled out by design.<br/><br/>Thanks to support of <a href="/en/faq/perfect_forward_secrecy">Perfect Forward Secrecy</a>, a potential attacker couldn’t even decrypt a user’s previous messages if they somehow managed to obtain the current private key of said user.<br/><br/>The algorithms and design decisions behind the cryptography in Threema are explained in the <a href="/press-files/2_documentation/cryptography_whitepaper.pdf">Cryptography Whitepaper</a>.</p> </div> </div> </div> </div> <div class="thr-section thr-section--textBig"> <div class="thr-wrapper"> <div class="container-fluid"> <div class="row justify-content-center justify-content-md-start"> <div class="thr-img-col col-10 col-md-7 offset-md-4 col-lg-5 offset-lg-0"> <img src="/images/illustration-metadata.png"> </div> <div class="col-10 col-md-8 offset-md-1 col-lg-6"> <span class="thr-title-icon thr-title-icon--metadata"></span> <div class="thr-bar-divider"></div> <h1 class="thr-section-title">Metadata Restraint as a Guiding Principle</h1> <p>Threema is designed to generate as little data on servers as technically possible. Groups* and contact lists are solely managed on the users’ devices, not on the server, messages are deleted immediately upon delivery, no log files are created, and no personally identifiable information is collected.</p> <div class="d-flex flex-wrap m-n1"> <a href="/en/blog/posts/push-notifications-and-data-privacy" class="thr-btn-secondary m-1"> Push notifications and data privacy </a> <a href="/en/blog/posts/threema-push" class="thr-btn-secondary m-1"> Threema Push for Android </a> </div> </div> </div> </div> </div> </div> <div class="thr-section thr-section--gutterBottomXXL thr-section--textBig"> <div class="thr-wrapper"> <div class="container-fluid"> <div class="row justify-content-center justify-content-md-start"> <div class="thr-img-col col-10 col-md-8 offset-md-4 col-lg-6 offset-lg-0 order-lg-2"> <img src="/images/open-source-illustration.png" alt="Open Source und regelmässige Audits"> </div> <div class="col-10 col-md-8 offset-md-1 col-lg-6 offset-lg-0"> <span class="thr-title-icon thr-title-icon--opensource"></span> <div class="thr-bar-divider"></div> <h1 class="thr-section-title">Open Source and External Audits</h1> <div class="text-secondary-gray600"><p>To ensure full transparency, the Threema <a href="/en/open-source">apps’ source code</a> is publicly accessible and open for review. Thanks to reproducible builds, anyone can verify that the published code (of the Android app, for the time being) corresponds to the apps in the stores.</p><p>On top of that, external experts are regularly commissioned to conduct systematic security audits, and the resulting <a href="/en/faq/code_audit">reports are published in their entirety.</a></p></div> </div> </div> </div> </div> </div> <div class="thr-section thr-security-anonymous-section"> <div class="thr-wrapper"> <div class="container-fluid"> <div class="row justify-content-center justify-content-md-start"> <div class="offset-lg-1 col-lg-4 col-md-12 col-10 thr-img-col"> <div> <div class="thr-mobile thr-img-center"> <div> <div class="thr-mobile-header">My Threema ID</div> <div class="thr-mobile-content"> <div class="thr-mobile-contact"> <div class="thr-avatar-element" thr-avatar-style="gray"></div> <div class="thr-contact-content"> <div class="w4 dark"></div> <div class="w10"></div> <div class="w10"></div> <div class="w10"></div> </div> </div> <div class="thr-mobile-my-id"> <div>G2WHL1A8</div> <img src="/images/qr_code_profile.png" class="qr-code" alt="Profile QR Code"/> </div> </div> </div> </div> </div> </div> <div class="thr-desc-col offset-md-1 col-lg-6 col-md-8 col-10 "> <span class="sp-pub-i-UserQuestionmark thr-sprite-icon"></span> <div class="thr-bar-divider"></div> <h1>Anonymous Use, No Account Required</h1> <p>It is not necessary to provide a phone number or email address in order to use Threema. When setting up the app, each user generates a <a href="/en/faq/threema_id">Threema ID</a>, which serves as unique identifier. Since this ID is a random sequence of characters, Threema can be used anonymously. No central user account is created.</p><p>In addition, Threema’s Android app can be <a href="/en/blog/posts/cash">purchased with cash</a>, which allows for complete buyer anonymity.</p> <div class="d-flex flex-wrap m-n1"> <a href="/en/blog/posts/anonymity" class="thr-btn-secondary m-1"> The ultimate privacy protection </a> <a href="/en/blog/posts/threema-libre" class="thr-btn-secondary m-1"> Threema without Google services </a> </div> </div> </div> </div> </div> </div> <div class="thr-section thr-address-book-section"> <div class="container-fluid"> <div class="row justify-content-center justify-content-md-start"> <div class="col-10 col-md-12 col-lg-5"> <div class="thr-img-col"> <div class="thr-contact-list thr-img-center thr-animation"> <div> <div class="sync-on"><span class="sp-pub-ri-Sync"></span></div> <div class="thr-switch thr-switch-on"></div> </div> <div> <div class="thr-mobile-contact"> <div class="thr-avatar-element" thr-avatar-size="medium" thr-avatar-style="gray"></div> <div class="thr-contact-content"> <div class="w5"></div> <div class="w4"></div> <div class="w3"></div> </div> </div> <div class="thr-mobile-contact"> <div class="thr-avatar-element" thr-avatar-size="medium" thr-avatar-style="gray"></div> <div class="thr-contact-content"> <div class="w7"></div> <div class="w5"></div> <div class="w3"></div> </div> </div> <div class="thr-mobile-contact"> <div class="thr-avatar-element" thr-avatar-size="medium" thr-avatar-style="gray"></div> <div class="thr-contact-content"> <div class="w6"></div> <div class="w4"></div> <div class="w3"></div> </div> </div> </div> </div> </div> </div> <div class="col-10 offset-md-1 col-md-8 col-lg-6"> <span class="sp-pub-i-Sync thr-sprite-icon"></span> <div class="thr-bar-divider"></div> <h1>Optional Contact Synchronization</h1> <p>Threema can be used without access to your address book. If you do grant access to the address book in order to retrieve your contacts’ Threema IDs, the contact data is transferred in one-way encrypted form and will not be stored on the server.</p> </div> </div> </div> </div> </div> <div class="thr-section thr-security-other-section"> <div class="container-fluid"> <div class="row justify-content-center"> <div class="col-lg-6 col-md-5 col-10 text-center thr-desc-col"> <span class="sp-pub-i-Encryption thr-sprite-icon"></span> <div class="thr-bar-divider mx-auto"></div> <h4>Strong Encryption on Mobile Device</h4> <p>As they are strongly encrypted, the chats and media files stored on the phone are optimally protected against unauthorized access. You can also use a PIN or your fingerprint to lock the app.</p> </div> <div class="col-lg-6 col-md-5 col-10 text-center thr-desc-col"> <span class="sp-pub-i-NoServer thr-sprite-icon"></span> <div class="thr-bar-divider mx-auto"></div> <h4>Decentralized Architecture</h4> <p>Chats, contact lists, and groups* are managed in decentralized manner directly on the involved devices; no data is stored on a server. Threema differs significantly from conventional messengers in this respect. </p> </div> <div class="col-lg-6 col-md-5 col-10 text-center thr-desc-col"> <span class="sp-pub-i-ShieldLock thr-sprite-icon"></span> <div class="thr-bar-divider mx-auto"></div> <h4>Rigorous Data Protection</h4> <p>Threema doesn’t compromise on security. With <a href="/en/blog/posts/threema-libre">Threema Libre</a> and our own push service <a href="/en/blog/posts/threema-push">Threema Push</a>, the Threema app for Android can even be used entirely without Google services. Due to <a href="/en/blog/posts/app-store">restrictions on Apple’s part</a>, iOS users are stuck with Apple’s own push service.</p> </div> </div> <p class="small text-center">*) Except groups that are centrally managed in Threema Broadcast.</p> </div> </div> <div class="thr-section thr-section--bgWhite thr-section--gutterBottomMedium thr-section--angleTopLeft"> <div class="container-fluid"> <div class="thr-textBox thr-textBox--teaser bg--work-primary thr-textBox--backgroundCircle"> <div class="thr-textBox--teaser-appIcon thr-svg align-self-center"> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 60 60"><g fill="none" fill-rule="evenodd"><rect width="60" height="60" fill="#004A7F" rx="3"/><path fill="#FFF" fill-rule="nonzero" d="m21.552 40.359-9.657 2.414 2.063-8.255c-2.044-2.693-3.235-5.93-3.235-9.41 0-9.369 8.63-16.963 19.277-16.963s19.277 7.594 19.277 16.962c0 9.369-8.63 16.963-19.277 16.963-3.03 0-5.897-.615-8.448-1.711Zm2.98-16.66h-.216a.879.879 0 0 0-.878.88v7.706c0 .486.393.88.878.88h11.368a.879.879 0 0 0 .879-.88v-7.707a.879.879 0 0 0-.88-.879h-.214v-2.184a5.466 5.466 0 0 0-5.472-5.46 5.465 5.465 0 0 0-5.466 5.46V23.7Zm8.75 0h-6.563v-2.183a3.28 3.28 0 0 1 3.28-3.277 3.28 3.28 0 0 1 3.282 3.277v2.183Z"/><path fill="#0096FF" d="M33.278 49.687a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm-11.833 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Zm23.666 0a3.28 3.28 0 1 1-6.56 0 3.28 3.28 0 1 1 6.56 0Z"/></g></svg> </div> <h2 class="thr-textBox--teaser-title text--negativeSelf align-self-center align-self-md-end mt-md-1 mb-0">Threema Work</h2> <h5 class="thr-textBox--teaser-subTitle font-weight-light text--negativeSelf mt-3 mb-0 mt-md-1">The ideal chat app for business purposes.</h5> <div class="thr-textBox--teaser-cta text--negative d-md-flex align-items-md-center mt-2 mt-md-4"> <a class="thr-btn thr-btn--white-work mr-md-3 d-block flex-shrink-0" href="/en/work/business-messenger">Learn more</a> <a class="thr-btn-secondary thr-btn-secondary--white mr-md-3 d-none d-md-block flex-shrink-0" href="https://work.threema.ch/en/cta/start-trial">Free trial</a> <p class="mb-0 text--small d-none d-lg-block text--muted">30 days, 30 users. No automatic renewal. No payment details required.</p> </div> </div> </div> </div> <div class="thr-section thr-support-faq-section inline-faq-section"> <div class="container-fluid"> <div class="row thr-faq-group thr-faq-group--normal"><div class="col-12"><h3 id="security-and-privacy">Security and Privacy</h3></div><div class="col-12 thr-faq-list"><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#why_secure" class="thr-flap__header collapsed"><a href="/en/faq/why_secure" onclick="return false;" class="thr-flap__title">What makes Threema secure?</a><div class="thr-flap__plus"></div></div><div id="why_secure" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/why_secure"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p> Threema uses tried-and-tested asymmetric cryptography to protect messages and calls between sender and recipient (and the communication between the app and the servers). Threema uses the open-source library <a href="https://nacl.cr.yp.to/" class="nw"> NaCl</a> for encryption. Since the Threema apps are <a href="/en/faq/source_code">open source</a>, anyone knowledgeable enough can confirm Threema’s security. </p> <p> <b>There are two layers of encryption:</b> The end-to-end layer between the conversation participants, and an additional layer to protect against eavesdropping of the connection between the app and the servers. The latter is necessary to ensure that an adversary who captures network packets (e.g. on a public wireless network) cannot even learn who is logging in and who is communicating with whom. </p> <p> All encryption and decryption happens directly on the device, and the user is in control over the key exchange. This guarantees that no third party – not even the server operators – can decrypt the content of the messages and calls. <br /> </p> <p> <b><b>Strength of the encryption</b>:</b> The asymmetric ECC based encryption used by Threema has a strength of 255 bits. According to a <a class="nw" href="https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-57pt1r4.pdf">NIST estimate</a> (page 54), this corresponds at least with the strength provided by 2048 bit RSA. <a class="nw" href="https://en.wikipedia.org/wiki/ECDH">ECDH</a> on <a class="nw" href="https://en.wikipedia.org/wiki/Curve25519">Curve25519</a> is used in conjunction with a hash function and a random nonce to derive a unique 256 bit symmetric key for each message. The stream cipher <a class="nw" href="https://en.wikipedia.org/wiki/Salsa20">XSalsa20</a> is then used to encrypt the message. A 128 bit message authentication code (MAC) is also added to each message to detect manipulations/forgeries. </p> <b>Perfect Forward Secrecy:</b> Threema supports Perfect Forward Secrecy. For more details, please refer to <a href="/en/faq/perfect_forward_secrecy">this FAQ entry</a>. <p></p> <p>For detailed technical information about the cryptography in Threema, read the <a href="/press-files/2_documentation/cryptography_whitepaper.pdf" class="nw" jqte-setlink="">Cryptography Whitepaper</a>.</p></div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#crypto_differences" class="thr-flap__header collapsed"><a href="/en/faq/crypto_differences" onclick="return false;" class="thr-flap__title">How does Threema compare to other messengers?</a><div class="thr-flap__plus"></div></div><div id="crypto_differences" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/crypto_differences"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p> To find out how Threema stacks up against other messengers like WhatsApp, Signal, or Telegram in terms of security, privacy, and features, please refer to our <a href="/en/messenger-comparison">comprehensive messenger comparison</a> and the <a href="/en/why-threema">in-depth comparison of Threema and WhatsApp</a>. </p></div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#privacy_protection" class="thr-flap__header collapsed"><a href="/en/faq/privacy_protection" onclick="return false;" class="thr-flap__title">What’s special about Threema’s privacy protection?</a><div class="thr-flap__plus"></div></div><div id="privacy_protection" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/privacy_protection"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p>Comprehensive privacy protection requires <a href="/en/faq/crypto_differences">solid message encryption</a>, but there is more to it.</p> <p><b>Full Anonymity</b><br /></p> <p> Threema can be used without providing any personal information whatsoever. Instead of a phone number, the <a href="/en/faq/threema_id">Threema ID</a> (a randomly generated eight-digit string) serves as unique identifier. Linking a phone number and/or email address to one’s Threema ID is optional. </p> <p><b>Metadata Restraint</b></p> <p> All data involved in communication other than the actual content is metadata. Serious privacy protection must include both protection of content and protection of metadata. The sole protection of content is insufficient because metadata allows to uniquely identify individuals, analyze their behavior, determine their circles of friends, detect their frequent locations, and monitor their communication behavior. Combined with data from other platforms, the picture that can be drawn of a person is much more detailed than one that could ever be drawn from message content alone. It’s likely that many messengers are used to systematically collect and analyze their users’ metadata. Threema, on the other hand, <a href="/en/faq/data">generates as little data as technically possible and only stores it as long as absolutely necessary.</a> </p> <p><b>Optional Contact Synchronization</b><br /></p> <p> Synchronizing your address book in order to retrieve your contacts’ Threema IDs (provided they have linked them, see above) is optional. If you don’t want to grant access to your address book, you can either scan your contacts’ Threema IDs or add them manually. </p> <p> In case you enable contact synchronization or link your ID with a phone number or email address, you can rest assured that Threema uses this information only temporarily for the specified purpose. <a href="/en/faq/data">Personal information is always hashed, both in transit and on disk.</a> </p> <p>To find out how Threema stacks up against other messengers in regard to privacy protection, please refer to the <a href="/en/messenger-comparison">messenger comparison</a>.</p></div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#data" class="thr-flap__header collapsed"><a href="/en/faq/data" onclick="return false;" class="thr-flap__title">Which data gets stored at Threema?</a><div class="thr-flap__plus"></div></div><div id="data" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/data"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p> Using Threema ought to generate as little data on our servers as possible – this is part of the concept. For that reason, data like contacts or group chats are stored in a decentralized way on user devices instead of on a Threema server. Our servers assume the role of a switch; messages and data are forwarded, but not permanently stored. Where there is no data, there is nothing to be accessed or misused. However, without some kind of (temporary) data storage, there cannot be any asynchronous communication. In the following, we will explain what kind of data we store, how we store it, and for how long. </p> <ul> <li> Messages and group chats: As soon as a message has been successfully delivered to the recipient, it is immediately deleted from the server. All messages and media are transmitted end-to-end encrypted in Threema. This means even if someone intercepted your message, it would be completely useless. Only the intended recipient is able to decrypt and read a message. </li> <li> No contact lists are stored when synchronizing contacts: The email addresses and phone numbers from your address book are anonymized (hashed) before they reach the server. Once the comparison is finished, they are immediately deleted from the server. </li> <li>Key pairs are generated in a decentralized way on your device. We will never know your private key, and therefore we cannot decrypt any message contents.</li> <li>Threema doesn’t log who is communicating with whom (i.e., which Threema IDs are communicating).</li> </ul> <p>Further information can be found in the <a class="nw" href="https://threema.ch/press-files/cryptography_whitepaper.pdf" jqte-setlink="">Cryptography Whitepaper</a>.</p></div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#source_code" class="thr-flap__header collapsed"><a href="/en/faq/source_code" onclick="return false;" class="thr-flap__title">Is Threema open source?</a><div class="thr-flap__plus"></div></div><div id="source_code" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/source_code"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p> Yes, to ensure full transparency, the Threema apps are open source. </p><p> Thanks to reproducible builds, there’s also a way to verify that the published code (of the Android app, for the time being) actually corresponds to the apps available for download in the app stores. </p><p> To learn how to download, build, and reproduce the Threema app’s code, please refer to the <a href="/en/open-source">Open Source subsite</a>. </p> </div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#crypto_local" class="thr-flap__header collapsed"><a href="/en/faq/crypto_local" onclick="return false;" class="thr-flap__title">Are messages stored in encrypted form on my device?</a><div class="thr-flap__plus"></div></div><div id="crypto_local" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/crypto_local"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p>Yes.</p> <p></p> <ul> <li> <b>Android</b>: Threema includes its own app-specific encryption based on AES-256 to protect stored messages, media, and your ID’s private key. The key used for this encryption is generated randomly the first time you start Threema, and can optionally be protected by setting a Master Key Passphrase in the settings, which we highly recommend. Without a passphrase, the encryption will only add obscurity due to the way hardware encryption is handled on Android. If you set a Master Key Passphrase, you will have to enter it after every restart of the device (and after the system has terminated the app due to low memory).<br /> <br /> Note: the PIN lock, which can be enabled independently of the Master Key Passphrase, does not offer additional encryption; it is simply a UI lock.<br /> <br /> </li> <li> <b>iOS</b>: Threema uses the iOS Data Protection feature to encrypt messages, images, etc. in the device’s flash storage. The key used for this encryption is linked to the device’s passcode. It is necessary to set a passcode in the system settings to use this feature. On newer models, iOS also uses hardware features for the encryption. Therefore, even a simple six-digit passcode offers a certain protection. For the highest protection against brute-force attacks, you should choose a longer, alphanumeric passcode.<br /> <br /> Note: The passcode lock that is built into the app itself does not offer additional encryption. This feature is intended to keep nosy people from reading your messages when you intentionally give them your phone for a short time for another purpose. Encryption with a six-digit code inside the app would not be sensible, as brute-force attacks would be trivial (since unlike iOS, an app cannot access special hardware features to protect the key).<br /> </li> </ul> <p></p> <p></p> <p>For detailed technical information about the cryptography in Threema, read the <a href="/press-files/cryptography_whitepaper.pdf">Cryptography Whitepaper</a>.</p> <p></p> <p></p> <p></p> <p></p> <p></p> </div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#crypto_authorities" class="thr-flap__header collapsed"><a href="/en/faq/crypto_authorities" onclick="return false;" class="thr-flap__title">Could you decrypt my messages, for example if you were required to by law enforcement?</a><div class="thr-flap__plus"></div></div><div id="crypto_authorities" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/crypto_authorities"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9">No, that is impossible, as we don’t have the secret keys of our users (your secret key never leaves your device). Our servers do need to know who is sending a message to whom, so that they can route it to the correct recipient, but they do not log this information, and cannot decrypt the message’s content.</div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#crypto_mitm" class="thr-flap__header collapsed"><a href="/en/faq/crypto_mitm" onclick="return false;" class="thr-flap__title">How do you protect yourself against man-in-the-middle (MITM) attacks with Threema?</a><div class="thr-flap__plus"></div></div><div id="crypto_mitm" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/crypto_mitm"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p>Threema allows you to verify that the ID of the person you are communicating with is really theirs by <a href="/en/faq/qr_code_expl">scanning their QR code</a>.</p> <p>If you are sure about your chat partner’s ID, then there’s no way for an attacker to spoof or intercept/decrypt a message from or to your chat partner.</p> <p> The connection between the app and the servers is secure against MITM attacks because the server authenticates itself to the app based on a public key that is hard-coded into the app and whose corresponding secret key is only known by the legitimate servers. </p> <p> Please note: Threema can only be as secure as the device that it is running on. Malware that runs in the background on your device can intercept and falsify data without being noticed. We highly recommend to always install the most recent operating system updates and to only use software from trusted sources. </p></div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#server_location" class="thr-flap__header collapsed"><a href="/en/faq/server_location" onclick="return false;" class="thr-flap__title">Where are the servers located?</a><div class="thr-flap__plus"></div></div><div id="server_location" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/server_location"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p>Threema GmbH runs its own servers in two high-security data centers of an “ISO 27001”-certified colocation partner in the Zurich area (Switzerland). </p> <p>The state-of-the-art data centers include biometric access control, full-height turnstiles, video surveillance, emergency power systems, fire protection, fail-safe air-conditioning, and a fully redundant Internet connection.</p> <p> <b>Group Calls</b> </p> <p> Apart from (some) group calls, Threema’s servers in Switzerland handle all communication. (For one-to-one calls, a direct connection will be established between the call participants if possible, which means that no server at all is involved after the call has been established.) For group calls, Threema media routers located abroad may be used to ensure a low latency and smooth communication: if group calls had to be routed through the servers in Switzerland from anywhere in the world, call participants might have a hard time to interact with each other due to high latency. </p> <p> The media routers abroad are unaware of the identities / Threema IDs of a group call’s participants, and all audio/video streams are end-to-end encrypted. For technical reasons, it is necessary for the media routers to know the IP addresses of a group call’s participants while the call is ongoing. However, this information is not logged and will be deleted from the working memory right after the group call has ended. </p></div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#addressbook_data" class="thr-flap__header collapsed"><a href="/en/faq/addressbook_data" onclick="return false;" class="thr-flap__title">Will my address book data be sent to your servers?</a><div class="thr-flap__plus"></div></div><div id="addressbook_data" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/addressbook_data"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p>That’s your decision – Threema can be used without any address book access whatsoever.</p> <p>By default, the synchronization is disabled, and no address book data will be read. In this case, you can add your Threema contacts manually (by typing in their IDs or scanning their QR codes).</p> <p> If you decide to enable the synchronization, email addresses and phone numbers from your address book will only be transmitted to the server in one-way encrypted (“hashed”) form and are additionally protected using TLS encryption. The servers only keep these hashes in volatile memory for a short time to determine the list of matching IDs, and then delete the hashes immediately. At no point are the hashes or the results of the synchronization written to disk.<br /> </p> <p> Due to the relatively low number of possible phone number combinations, it is theoretically possible to crack hashes of phone numbers by trying all possibilities. This is due to the nature of hashes and phone numbers and cannot be solved differently (using salts like for hashing passwords does not work for this kind of data matching). Therefore we treat phone number hashes with the same care as if they were raw/unhashed phone numbers. </p> </div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#code_audit" class="thr-flap__header collapsed"><a href="/en/faq/code_audit" onclick="return false;" class="thr-flap__title">How does Threema audit its code?</a><div class="thr-flap__plus"></div></div><div id="code_audit" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/code_audit"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p> The Threema apps are <a href="/en/faq/source_code">open source</a>, allowing anyone to audit Threema’s code on their own. Furthermore, external experts are commissioned to conduct comprehensive security audits on a regular basis. The most recent audits are listed below. </p> <ul> <li>2024: Audit by Cure53 of the new desktop app, see <a href="https://threema.ch/en/blog/posts/threema-desktop-open-source">blog post</a> and <a href="https://threema.ch/press-files/2_documentation/audit-report-threema-desktop-01-2024.pdf">audit report</a></li> <li>2023: Security analysis of the “Ibex” communication protocol by security researchers from the Chair of Applied Cryptography at the University of Erlangen-Nuremberg, see <a href="/en/blog/posts/security-proof-ibex">blog post</a> and <a href="/press-files/2_documentation/security_analysis_ibex_2023.pdf">analysis</a></li> <li>2020: Audit by Cure53, see <a href="/en/blog/posts/audit-2020-en">blog post</a> and <a href="/press-files/2_documentation/security_audit_report_threema_2020.pdf">audit report</a></li> <li> 2019: Audit by Lab for IT Security of the Münster University of Applied Sciences, see <a href="/en/blog/posts/audit19en">blog post</a> and <a href="/press-files/2_documentation/security_audit_report_threema_2019.pdf">audit report</a> </li> </ul> <p>For a comprehensive documentation of the algorithms and protocols used in Threema, please refer to the <a href="/press-files/2_documentation/cryptography_whitepaper.pdf">Cryptography Whitepaper</a>.</p> </div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#bug-bounty" class="thr-flap__header collapsed"><a href="/en/faq/bug-bounty" onclick="return false;" class="thr-flap__title">Is there a bug bounty program?</a><div class="thr-flap__plus"></div></div><div id="bug-bounty" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/bug-bounty"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p>There is a bug bounty program for reports concerning Threema’s security. If you discover a security issue, please file a report on <a class="nw" href="https://app.gobugfree.com/programs/threema">GObugfree</a> (where all the details, including the bounty levels, are listed).</p> Please report bugs concerning Threema’s apps using the <a href="https://threema.ch/en/support#contact">support form</a>.</div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#compliance" class="thr-flap__header collapsed"><a href="/en/faq/compliance" onclick="return false;" class="thr-flap__title">Is the use of Threema compliant with privacy laws?</a><div class="thr-flap__plus"></div></div><div id="compliance" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/compliance"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p> Threema meets the requirements of the <a class="nw" href="https://eur-lex.europa.eu/legal-content/DE/TXT/?uri=CELEX%3A32016R0679">European General Data Protection Regulation</a> (GDPR) and is also subject to Switzerland’s <a class="nw" href="https://www.admin.ch/opc/en/classified-compilation/19920153/index.html">Federal Act on Data Protection</a> (DSG). </p> <p>Threema does not use phone numbers to address users and can be used anonymously without uploading address book data. It is therefore also suited for childern under the age of 16.</p> <p>In contrast to conventional messengers, you can therefore be sure to comply with privacy laws when using Threema.</p> <div class="status2 info primary"> <div></div> <div> In November 2021, the FZI Research Center for Information Technology in Karlsruhe, Germany, released a comprehensive legal study on the corporate use of messaging services as well as a compact practical guide (both in German), see <a class="nw" href="/en/work/blog/posts/legal-study">blog post</a>. </div> </div> </div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#get_my_data" class="thr-flap__header collapsed"><a href="/en/faq/get_my_data" onclick="return false;" class="thr-flap__title">How can I find out what information is stored about my ID on Threema’s server?</a><div class="thr-flap__plus"></div></div><div id="get_my_data" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/get_my_data"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p>To retrieve your ID’s inventory data that’s stored on the Threema server, simply send “info” to the Threema ID <code>*MY3DATA</code>, and you’ll immediately receive a reply in machine-readable form (JSON).</p> <p>If you’re reading this page on the device where Threema is installed, simply open the following link, and then tap “Send”: <a href="https://threema.id/%2AMY3DATA?text=info"> https://threema.id/%2AMY3DATA?text=info </a></p> <p>Explanation of the JSON keys:</p> <ul> <li>identity: Threema ID</li> <li>publicKey: Base64 coded</li> <li>issueDate: date of ID creation</li> <li>lastLogin: date of last login</li> <li>mobileNoHash: hash of linked phone number</li> <li>emailHash: hash of linked email address</li> <li>featureMask: bit mask of features supported by the Threema version in use</li> <ul> <li>0x01: audio messages</li> <li>0x02: group chat</li> <li>0x04: polls</li> <li>0x08: file transfer</li> <li>0x10: calls</li> <li>0x20: video calls</li> </ul> <li>pushtoken/voippushtoken: push token of the push services in use (GCM/FCM, APNS, HMS). This key is obsolete if the “pushtokens” key is present</li> <li>pushtokens: list of devices that have a push token associated to them</li> <ul> <li>device_id: base64-encoded bytes of the unsigned 64-bit integer that identifies a device</li> <li>push_token/voip_token:</li> <ul> <li>data: base64-encoded token</li> <li>timestamp: unix timestamp when the token was set</li> <li>type: describes the type of the token (HMS, Apple, FCM)</li> </ul> </ul> <li>pushsound/pushgroupsound: name of the chosen sound file for push messages (not used on all platforms)<br /></li> <li>revocationKey: information about revocation password, if set<br /></li> </ul> <p> Editable inventory data can be modified or deleted at any time in the Threema app (in the “My Profile” (Android) or “Profile” (iOS) tab) with immediate effect (see <a href="/en/faq/unlink">this FAQ article</a> for more information). To permanently delete your Threema ID’s inventory data, please <a href="/en/faq/revoke">revoke your ID</a>. </p></div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#privacy_push" class="thr-flap__header collapsed"><a href="/en/faq/privacy_push" onclick="return false;" class="thr-flap__title">What kind of data is transmitted via push notification services?</a><div class="thr-flap__plus"></div></div><div id="privacy_push" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/privacy_push"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p><b>Android</b></p> <p>To inform Android users about incoming messages in the background, you can use Threema’s own and independent push service “<a href="/en/faq/threema_push">Threema Push</a>,” which doesn’t generate metadata for third parties.</p> <p> Otherwise, Threema uses the push service already installed on the device, i.e., Firebase Cloud Messaging (FCM) by Google (or Huawei’s push kit HMS). The app then fetches messages directly from the Threema servers, decrypts them, and displays a local notification. Neither contents nor details about messages are transmitted via FCM (the FCM payload is empty), and all of Firebase’s tracking and analysis components have been removed. </p> <p><b>iOS</b></p> <p> Threema uses the Apple Push Notification Service (APNS) to inform recipients with iOS about new messages while the app is closed or in the background. The APNS message contains a payload that has been encrypted with a symmetric key, which is negotiated between the app and the Threema servers and is not known to Apple. </p> <p>Within this encrypted payload, the Threema ID and nickname of the sender, the message ID, and the fact whether it is a direct or a group message, are transmitted.</p> <p> The Threema app is started in the background for each incoming push notification, decrypts the push payload, downloads the corresponding message directly from the Threema servers, decrypts it, and shows a local message preview (if enabled) and the contact name of the sender. </p></div></div></div></div></div><div class="thr-faq thr-flap nw-always"><div data-toggle="collapse" data-target="div#perfect_forward_secrecy" class="thr-flap__header collapsed"><a href="/en/faq/perfect_forward_secrecy" onclick="return false;" class="thr-flap__title">What is Perfect Forward Secrecy?</a><div class="thr-flap__plus"></div></div><div id="perfect_forward_secrecy" class="thr-flap__content position-relative collapse"><div class="thr-flap__contentInner"><button class="thr-copy position-absolute top-0 right-0 mt-2 mr-3" type="button" data-copy="https://threema.ch/en/faq/perfect_forward_secrecy"><span class="thr-copy__default text--brand-500"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9 15H5c-1.38 0-2.56-.49-3.54-1.46S0 11.38 0 10s.49-2.56 1.46-3.54S3.61 5 5 5h4v2H5c-.83 0-1.54.29-2.13.88s-.88 1.29-.88 2.13.29 1.54.88 2.13 1.29.88 2.13.88h4v2Zm-3-4V9h8v2H6Zm5 4v-2h4c.83 0 1.54-.29 2.13-.88s.88-1.29.88-2.13-.29-1.54-.88-2.13-1.29-.88-2.13-.88h-4v-2h4c1.38 0 2.56.49 3.54 1.46S20 8.59 20 9.98s-.49 2.56-1.46 3.54-2.15 1.46-3.54 1.46h-4Z" fill="currentColor"/></svg> </span><span class="thr-copy__success"><?xml version="1.0" encoding="UTF-8"?> <svg width="24px" height="24px" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Icon / Checkmark</title> <g id="Icon-/-Checkmark" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <polygon id="Checkmark" fill="#000000" points="9.06550686 16.3487067 20.5913474 4.82286617 22.005561 6.23707973 9.06550686 19.1771338 1.99443905 12.106066 3.40865261 10.6918525"></polygon> </g> </svg></span></button><div class="row"><div class="col-11 col-md-9"><p>A cryptographic system is said to have Perfect Forward Secrecy (PFS) if it’s not possible for an attacker who obtains a user’s private key in the present to use this key to decrypt messages the user has sent or received in the past.</p> <p>This property is achieved by using separate keys for individual sessions or short periods of time instead of always using one and the same key.</p> <p> Threema supports Perfect Forward Secrecy both on the transport layer and on the end-to-end layer. Technical information can be found in the <a href="https://threema.ch/press-files/cryptography_whitepaper.pdf">Cryptography Whitepaper</a>. </p></div></div></div></div></div><div class="text-center mt-5"><a href="/en/support" class="thr-btn" title="All FAQs">All FAQs</a></div></div></div> </div> </div> </main> <footer class="border-top footer mb-4 pt-5"><div class="container-fluid container-fluid--xl"><div class="footer__row mb-3"><div class="footer__block"><span class="thr-ft-title">Products</span><a class="thr-ft-link" href="/en" title="Overview">Overview</a><a class="thr-ft-link active" href="/en/secure-messenger" title="Threema">Threema</a><a class="thr-ft-link" href="/en/work/business-messenger" title="Threema Work">Threema Work</a><a class="thr-ft-link" href="/en/broadcast" title="Threema Broadcast">Threema Broadcast</a><a class="thr-ft-link" href="/en/onprem" title="Threema OnPrem">Threema OnPrem</a><a class="thr-ft-link" href="/en/gateway" title="Threema Gateway">Threema 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