CINXE.COM
The end of SHA-1 on the Public Web - Mozilla Security Blog
<!DOCTYPE html> <html lang="en-US" dir="ltr" class="no-js"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="license" href="#license"> <link rel="profile" href="https://gmpg.org/xfn/11"> <link rel="shortcut icon" type="image/png" href="https://blog.mozilla.org/security/wp-content/themes/frontierline/img/favicon.png"> <!--[if IE]> <meta name="MSSmartTagsPreventParsing" content="true"> <meta http-equiv="imagetoolbar" content="no"> <meta http-equiv="X-UA-Compatible" content="IE=Edge"> <![endif]--> <!--[if lte IE 8]> <script src="https://blog.mozilla.org/security/wp-content/themes/frontierline/js/html5.js"></script> <link rel="shortcut icon" type="image/x-icon" href="https://blog.mozilla.org/security/wp-content/themes/frontierline/img/favicon.ico"> <link rel="stylesheet" type="text/css" media="all" href="https://blog.mozilla.org/security/wp-content/themes/frontierline/oldIE.css"> <![endif]--> <meta name="title" content="The end of SHA-1 on the Public Web – Mozilla Security Blog"> <meta name="description" content="Our deprecation plan for the SHA-1 algorithm in the public Web, first announced in 2015, is drawing to a close. Today a team of researchers from CWI Amsterdam and Google ..."> <meta property="og:site_name" content="Mozilla Security Blog"> <meta property="og:url" content="https://blog.mozilla.org/security/2017/02/23/the-end-of-sha-1-on-the-public-web"> <meta property="og:title" content="The end of SHA-1 on the Public Web – Mozilla Security Blog"> <meta property="og:description" content="Our deprecation plan for the SHA-1 algorithm in the public Web, first announced in 2015, is drawing to a close. Today a team of researchers from CWI Amsterdam and Google ..."> <meta property="twitter:title" content="The end of SHA-1 on the Public Web – Mozilla Security Blog"> <meta property="twitter:description" content="Our deprecation plan for the SHA-1 algorithm in the public Web, first announced in 2015, is drawing to a close. Today a team of researchers from CWI Amsterdam and Google ..."> <meta name="twitter:card" content="summary"> <meta name='robots' content='index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1' /> <meta name="blog-name" content="Mozilla Security Blog" /> <!-- This site is optimized with the Yoast SEO plugin v22.5 - https://yoast.com/wordpress/plugins/seo/ --> <title>The end of SHA-1 on the Public Web - Mozilla Security Blog</title> <link rel="canonical" href="https://blog.mozilla.org/security/2017/02/23/the-end-of-sha-1-on-the-public-web/" /> <meta name="twitter:label1" content="Written by" /> <meta name="twitter:data1" content="J.C. Jones" /> <meta name="twitter:label2" content="Est. reading time" /> <meta name="twitter:data2" content="1 minute" /> <script type="application/ld+json" class="yoast-schema-graph">{"@context":"https://schema.org","@graph":[{"@type":"WebPage","@id":"https://blog.mozilla.org/security/2017/02/23/the-end-of-sha-1-on-the-public-web/","url":"https://blog.mozilla.org/security/2017/02/23/the-end-of-sha-1-on-the-public-web/","name":"The end of SHA-1 on the Public Web - Mozilla Security Blog","isPartOf":{"@id":"https://blog.mozilla.org/security/#website"},"datePublished":"2017-02-23T23:15:57+00:00","dateModified":"2017-02-23T23:15:57+00:00","author":{"@id":"https://blog.mozilla.org/security/#/schema/person/ff7006d539a011babd1a38233028c96a"},"breadcrumb":{"@id":"https://blog.mozilla.org/security/2017/02/23/the-end-of-sha-1-on-the-public-web/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https://blog.mozilla.org/security/2017/02/23/the-end-of-sha-1-on-the-public-web/"]}]},{"@type":"BreadcrumbList","@id":"https://blog.mozilla.org/security/2017/02/23/the-end-of-sha-1-on-the-public-web/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://blog.mozilla.org/security/"},{"@type":"ListItem","position":2,"name":"The end of SHA-1 on the Public Web"}]},{"@type":"WebSite","@id":"https://blog.mozilla.org/security/#website","url":"https://blog.mozilla.org/security/","name":"Mozilla Security Blog","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://blog.mozilla.org/security/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https://blog.mozilla.org/security/#/schema/person/ff7006d539a011babd1a38233028c96a","name":"J.C. Jones","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https://blog.mozilla.org/security/#/schema/person/image/d063fc46e7671301c178b2781210dff7","url":"https://secure.gravatar.com/avatar/64eb1412c9354cf356df31936368cdac?s=96&d=identicon&r=g","contentUrl":"https://secure.gravatar.com/avatar/64eb1412c9354cf356df31936368cdac?s=96&d=identicon&r=g","caption":"J.C. Jones"},"description":"Keeping people safe on the 'net. Cryptography Engineering lead for Firefox.","sameAs":["https://tacticalsecret.com/","https://x.com/JamesPugJones"]}]}</script> <!-- / Yoast SEO plugin. --> <link rel="alternate" type="application/rss+xml" title="Mozilla Security Blog » Feed" href="https://blog.mozilla.org/security/feed/" /> <link rel="alternate" type="application/rss+xml" title="Mozilla Security Blog » Comments Feed" href="https://blog.mozilla.org/security/comments/feed/" /> <link rel='stylesheet' id='wp-block-library-css' href='https://blog.mozilla.org/security/wp-includes/css/dist/block-library/style.min.css?ver=6.3.5' type='text/css' media='all' /> <style id='co-authors-plus-coauthors-style-inline-css' type='text/css'> .wp-block-co-authors-plus-coauthors.is-layout-flow [class*=wp-block-co-authors-plus]{display:inline} </style> <style id='co-authors-plus-avatar-style-inline-css' type='text/css'> .wp-block-co-authors-plus-avatar :where(img){height:auto;max-width:100%;vertical-align:bottom}.wp-block-co-authors-plus-coauthors.is-layout-flow .wp-block-co-authors-plus-avatar :where(img){vertical-align:middle}.wp-block-co-authors-plus-avatar:is(.alignleft,.alignright){display:table}.wp-block-co-authors-plus-avatar.aligncenter{display:table;margin-inline:auto} </style> <style id='co-authors-plus-image-style-inline-css' type='text/css'> .wp-block-co-authors-plus-image{margin-bottom:0}.wp-block-co-authors-plus-image :where(img){height:auto;max-width:100%;vertical-align:bottom}.wp-block-co-authors-plus-coauthors.is-layout-flow .wp-block-co-authors-plus-image :where(img){vertical-align:middle}.wp-block-co-authors-plus-image:is(.alignfull,.alignwide) :where(img){width:100%}.wp-block-co-authors-plus-image:is(.alignleft,.alignright){display:table}.wp-block-co-authors-plus-image.aligncenter{display:table;margin-inline:auto} </style> <style id='classic-theme-styles-inline-css' type='text/css'> /*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} </style> <style id='global-styles-inline-css' type='text/css'> body{--wp--preset--color--black: #000000;--wp--preset--color--cyan-bluish-gray: #abb8c3;--wp--preset--color--white: #ffffff;--wp--preset--color--pale-pink: #f78da7;--wp--preset--color--vivid-red: #cf2e2e;--wp--preset--color--luminous-vivid-orange: #ff6900;--wp--preset--color--luminous-vivid-amber: #fcb900;--wp--preset--color--light-green-cyan: #7bdcb5;--wp--preset--color--vivid-green-cyan: #00d084;--wp--preset--color--pale-cyan-blue: #8ed1fc;--wp--preset--color--vivid-cyan-blue: #0693e3;--wp--preset--color--vivid-purple: #9b51e0;--wp--preset--gradient--vivid-cyan-blue-to-vivid-purple: linear-gradient(135deg,rgba(6,147,227,1) 0%,rgb(155,81,224) 100%);--wp--preset--gradient--light-green-cyan-to-vivid-green-cyan: linear-gradient(135deg,rgb(122,220,180) 0%,rgb(0,208,130) 100%);--wp--preset--gradient--luminous-vivid-amber-to-luminous-vivid-orange: linear-gradient(135deg,rgba(252,185,0,1) 0%,rgba(255,105,0,1) 100%);--wp--preset--gradient--luminous-vivid-orange-to-vivid-red: linear-gradient(135deg,rgba(255,105,0,1) 0%,rgb(207,46,46) 100%);--wp--preset--gradient--very-light-gray-to-cyan-bluish-gray: linear-gradient(135deg,rgb(238,238,238) 0%,rgb(169,184,195) 100%);--wp--preset--gradient--cool-to-warm-spectrum: linear-gradient(135deg,rgb(74,234,220) 0%,rgb(151,120,209) 20%,rgb(207,42,186) 40%,rgb(238,44,130) 60%,rgb(251,105,98) 80%,rgb(254,248,76) 100%);--wp--preset--gradient--blush-light-purple: linear-gradient(135deg,rgb(255,206,236) 0%,rgb(152,150,240) 100%);--wp--preset--gradient--blush-bordeaux: linear-gradient(135deg,rgb(254,205,165) 0%,rgb(254,45,45) 50%,rgb(107,0,62) 100%);--wp--preset--gradient--luminous-dusk: linear-gradient(135deg,rgb(255,203,112) 0%,rgb(199,81,192) 50%,rgb(65,88,208) 100%);--wp--preset--gradient--pale-ocean: linear-gradient(135deg,rgb(255,245,203) 0%,rgb(182,227,212) 50%,rgb(51,167,181) 100%);--wp--preset--gradient--electric-grass: linear-gradient(135deg,rgb(202,248,128) 0%,rgb(113,206,126) 100%);--wp--preset--gradient--midnight: linear-gradient(135deg,rgb(2,3,129) 0%,rgb(40,116,252) 100%);--wp--preset--font-size--small: 13px;--wp--preset--font-size--medium: 20px;--wp--preset--font-size--large: 36px;--wp--preset--font-size--x-large: 42px;--wp--preset--spacing--20: 0.44rem;--wp--preset--spacing--30: 0.67rem;--wp--preset--spacing--40: 1rem;--wp--preset--spacing--50: 1.5rem;--wp--preset--spacing--60: 2.25rem;--wp--preset--spacing--70: 3.38rem;--wp--preset--spacing--80: 5.06rem;--wp--preset--shadow--natural: 6px 6px 9px rgba(0, 0, 0, 0.2);--wp--preset--shadow--deep: 12px 12px 50px rgba(0, 0, 0, 0.4);--wp--preset--shadow--sharp: 6px 6px 0px rgba(0, 0, 0, 0.2);--wp--preset--shadow--outlined: 6px 6px 0px -3px rgba(255, 255, 255, 1), 6px 6px rgba(0, 0, 0, 1);--wp--preset--shadow--crisp: 6px 6px 0px rgba(0, 0, 0, 1);}:where(.is-layout-flex){gap: 0.5em;}:where(.is-layout-grid){gap: 0.5em;}body .is-layout-flow > .alignleft{float: left;margin-inline-start: 0;margin-inline-end: 2em;}body .is-layout-flow > .alignright{float: right;margin-inline-start: 2em;margin-inline-end: 0;}body .is-layout-flow > .aligncenter{margin-left: auto !important;margin-right: auto !important;}body .is-layout-constrained > .alignleft{float: left;margin-inline-start: 0;margin-inline-end: 2em;}body .is-layout-constrained > .alignright{float: right;margin-inline-start: 2em;margin-inline-end: 0;}body .is-layout-constrained > .aligncenter{margin-left: auto !important;margin-right: auto !important;}body .is-layout-constrained > :where(:not(.alignleft):not(.alignright):not(.alignfull)){max-width: var(--wp--style--global--content-size);margin-left: auto !important;margin-right: auto !important;}body .is-layout-constrained > .alignwide{max-width: var(--wp--style--global--wide-size);}body .is-layout-flex{display: flex;}body .is-layout-flex{flex-wrap: wrap;align-items: center;}body .is-layout-flex > *{margin: 0;}body .is-layout-grid{display: grid;}body .is-layout-grid > *{margin: 0;}:where(.wp-block-columns.is-layout-flex){gap: 2em;}:where(.wp-block-columns.is-layout-grid){gap: 2em;}:where(.wp-block-post-template.is-layout-flex){gap: 1.25em;}:where(.wp-block-post-template.is-layout-grid){gap: 1.25em;}.has-black-color{color: var(--wp--preset--color--black) !important;}.has-cyan-bluish-gray-color{color: var(--wp--preset--color--cyan-bluish-gray) !important;}.has-white-color{color: var(--wp--preset--color--white) !important;}.has-pale-pink-color{color: var(--wp--preset--color--pale-pink) !important;}.has-vivid-red-color{color: var(--wp--preset--color--vivid-red) !important;}.has-luminous-vivid-orange-color{color: var(--wp--preset--color--luminous-vivid-orange) !important;}.has-luminous-vivid-amber-color{color: var(--wp--preset--color--luminous-vivid-amber) !important;}.has-light-green-cyan-color{color: var(--wp--preset--color--light-green-cyan) !important;}.has-vivid-green-cyan-color{color: var(--wp--preset--color--vivid-green-cyan) !important;}.has-pale-cyan-blue-color{color: var(--wp--preset--color--pale-cyan-blue) !important;}.has-vivid-cyan-blue-color{color: var(--wp--preset--color--vivid-cyan-blue) !important;}.has-vivid-purple-color{color: var(--wp--preset--color--vivid-purple) !important;}.has-black-background-color{background-color: var(--wp--preset--color--black) !important;}.has-cyan-bluish-gray-background-color{background-color: var(--wp--preset--color--cyan-bluish-gray) !important;}.has-white-background-color{background-color: var(--wp--preset--color--white) !important;}.has-pale-pink-background-color{background-color: var(--wp--preset--color--pale-pink) !important;}.has-vivid-red-background-color{background-color: var(--wp--preset--color--vivid-red) !important;}.has-luminous-vivid-orange-background-color{background-color: var(--wp--preset--color--luminous-vivid-orange) !important;}.has-luminous-vivid-amber-background-color{background-color: var(--wp--preset--color--luminous-vivid-amber) !important;}.has-light-green-cyan-background-color{background-color: var(--wp--preset--color--light-green-cyan) !important;}.has-vivid-green-cyan-background-color{background-color: var(--wp--preset--color--vivid-green-cyan) !important;}.has-pale-cyan-blue-background-color{background-color: var(--wp--preset--color--pale-cyan-blue) !important;}.has-vivid-cyan-blue-background-color{background-color: var(--wp--preset--color--vivid-cyan-blue) !important;}.has-vivid-purple-background-color{background-color: var(--wp--preset--color--vivid-purple) !important;}.has-black-border-color{border-color: var(--wp--preset--color--black) !important;}.has-cyan-bluish-gray-border-color{border-color: var(--wp--preset--color--cyan-bluish-gray) !important;}.has-white-border-color{border-color: var(--wp--preset--color--white) !important;}.has-pale-pink-border-color{border-color: var(--wp--preset--color--pale-pink) !important;}.has-vivid-red-border-color{border-color: var(--wp--preset--color--vivid-red) !important;}.has-luminous-vivid-orange-border-color{border-color: var(--wp--preset--color--luminous-vivid-orange) !important;}.has-luminous-vivid-amber-border-color{border-color: var(--wp--preset--color--luminous-vivid-amber) !important;}.has-light-green-cyan-border-color{border-color: var(--wp--preset--color--light-green-cyan) !important;}.has-vivid-green-cyan-border-color{border-color: var(--wp--preset--color--vivid-green-cyan) !important;}.has-pale-cyan-blue-border-color{border-color: var(--wp--preset--color--pale-cyan-blue) !important;}.has-vivid-cyan-blue-border-color{border-color: var(--wp--preset--color--vivid-cyan-blue) !important;}.has-vivid-purple-border-color{border-color: var(--wp--preset--color--vivid-purple) !important;}.has-vivid-cyan-blue-to-vivid-purple-gradient-background{background: var(--wp--preset--gradient--vivid-cyan-blue-to-vivid-purple) !important;}.has-light-green-cyan-to-vivid-green-cyan-gradient-background{background: var(--wp--preset--gradient--light-green-cyan-to-vivid-green-cyan) !important;}.has-luminous-vivid-amber-to-luminous-vivid-orange-gradient-background{background: var(--wp--preset--gradient--luminous-vivid-amber-to-luminous-vivid-orange) !important;}.has-luminous-vivid-orange-to-vivid-red-gradient-background{background: var(--wp--preset--gradient--luminous-vivid-orange-to-vivid-red) !important;}.has-very-light-gray-to-cyan-bluish-gray-gradient-background{background: var(--wp--preset--gradient--very-light-gray-to-cyan-bluish-gray) !important;}.has-cool-to-warm-spectrum-gradient-background{background: var(--wp--preset--gradient--cool-to-warm-spectrum) !important;}.has-blush-light-purple-gradient-background{background: var(--wp--preset--gradient--blush-light-purple) !important;}.has-blush-bordeaux-gradient-background{background: var(--wp--preset--gradient--blush-bordeaux) !important;}.has-luminous-dusk-gradient-background{background: var(--wp--preset--gradient--luminous-dusk) !important;}.has-pale-ocean-gradient-background{background: var(--wp--preset--gradient--pale-ocean) !important;}.has-electric-grass-gradient-background{background: var(--wp--preset--gradient--electric-grass) !important;}.has-midnight-gradient-background{background: var(--wp--preset--gradient--midnight) !important;}.has-small-font-size{font-size: var(--wp--preset--font-size--small) !important;}.has-medium-font-size{font-size: var(--wp--preset--font-size--medium) !important;}.has-large-font-size{font-size: var(--wp--preset--font-size--large) !important;}.has-x-large-font-size{font-size: var(--wp--preset--font-size--x-large) !important;} .wp-block-navigation a:where(:not(.wp-element-button)){color: inherit;} :where(.wp-block-post-template.is-layout-flex){gap: 1.25em;}:where(.wp-block-post-template.is-layout-grid){gap: 1.25em;} :where(.wp-block-columns.is-layout-flex){gap: 2em;}:where(.wp-block-columns.is-layout-grid){gap: 2em;} .wp-block-pullquote{font-size: 1.5em;line-height: 1.6;} </style> <link rel='stylesheet' id='frontierline-parent-css' href='https://blog.mozilla.org/security/wp-content/themes/frontierline/style.css?ver=6.3.5' type='text/css' media='all' /> <link rel='stylesheet' id='frontierline-css' href='https://blog.mozilla.org/security/wp-content/themes/frontierline-firefox/style.css?ver=1686919482' type='text/css' media='all' /> <script type='text/javascript' src='https://blog.mozilla.org/wp-content/mu-plugins/mozilla-custom/ga-snippet.js?ver=.4' id='ga-snippet-js'></script> <script type='text/javascript' src='https://blog.mozilla.org/security/wp-includes/js/jquery/jquery.min.js?ver=3.7.0' id='jquery-core-js'></script> <script type='text/javascript' src='https://blog.mozilla.org/security/wp-includes/js/jquery/jquery-migrate.min.js?ver=3.4.1' id='jquery-migrate-js'></script> <link rel="https://api.w.org/" href="https://blog.mozilla.org/security/wp-json/" /><link rel="alternate" type="application/json" href="https://blog.mozilla.org/security/wp-json/wp/v2/posts/2196" /><link rel="EditURI" type="application/rsd+xml" title="RSD" href="https://blog.mozilla.org/security/xmlrpc.php?rsd" /> <link rel='shortlink' href='https://blog.mozilla.org/security/?p=2196' /> <link rel="alternate" type="application/json+oembed" href="https://blog.mozilla.org/security/wp-json/oembed/1.0/embed?url=https%3A%2F%2Fblog.mozilla.org%2Fsecurity%2F2017%2F02%2F23%2Fthe-end-of-sha-1-on-the-public-web%2F" /> <link rel="alternate" type="text/xml+oembed" href="https://blog.mozilla.org/security/wp-json/oembed/1.0/embed?url=https%3A%2F%2Fblog.mozilla.org%2Fsecurity%2F2017%2F02%2F23%2Fthe-end-of-sha-1-on-the-public-web%2F&format=xml" /> </head> <body class="post-template-default single single-post postid-2196 single-format-standard color-scheme-none pattern-none" data-blogname="Mozilla Security Blog"> <nav id="nav-global" class="nav-global can-stick"> <div class="content"> <div class="logo"><a href="https://www.mozilla.org/?utm_source=blog.mozilla.org&utm_medium=referral&utm_campaign=blog-nav" rel="external" title="Visit mozilla.org">Mozilla</a></div> <div class="nav-mozilla"> <span class="toggle" role="button" aria-controls="nav-mozilla-menu" aria-expanded="false" tabindex="0">Menu</span> <ul class="nav-mozilla-menu" id="nav-mozilla-menu"> <li class="nav-global-health"><a href="https://www.mozilla.org/about/?utm_source=blog.mozilla.org&utm_medium=referral&utm_campaign=blog-nav" rel="external">About Mozilla</a></li> <li class="nav-global-tech"><a href="https://www.mozilla.org/firefox/products/?utm_source=blog.mozilla.org&utm_medium=referral&utm_campaign=blog-nav" rel="external">Products</a></li> <li class="nav-global-donate"><a href="https://donate.mozilla.org/?presets=50,30,20,10&amount=30&currency=usd&utm_source=blog.mozilla.org&utm_medium=referral&utm_campaign=blog-nav" rel="external">Give</a></li> <li class="nav-global-firefox"><a href="https://www.mozilla.org/firefox/?utm_source=blog.mozilla.org&utm_medium=referral&utm_campaign=blog-nav" rel="external">Discover Firefox</a></li> </ul> </div> </div> </nav> <header id="masthead" class="section"> <div class="site-id"> <div class="site-title-wrap content"> <a href="https://blog.mozilla.org/security/" rel="home" title="Go to the front page"> <h4 id="site-title"><span>Mozilla Security Blog</span></h4> </a> </div> </div> </header> <div class="site-wrap"> <nav id="nav-util" class="can-stick "> <ul class="content"> <li class="nav-util-search"> <form id="search" class="fm-search" method="get" action="https://blog.mozilla.org/security/"> <fieldset> <p> <label for="s">Search this site</label> <input type="search" value="" name="s" id="s"> <button type="submit" class="button button-minor">Search</button> </p> </fieldset> </form> </li> </ul> </nav> <main id="content"> <div class="content"> <article id="post-2196" class="post post-2196 type-post status-publish format-standard hentry category-ca-program category-security tag-tls"> <header class="entry-header"> <div class="entry-tools"> <div class="categories"> <b>Categories:</b> <a href="https://blog.mozilla.org/security/category/ca-program/" rel="category tag">CA Program</a> <a href="https://blog.mozilla.org/security/category/security/" rel="category tag">Security</a> </div> </div> <h1 class="entry-title"> The end of SHA-1 on the Public Web </h1> <div class="entry-info"> <address class="vcard"> J.C. Jones </address> <time class="date published" datetime="2017-02-23T15:15:57-08:00">February 23, 2017</time> </div> </header> <div class="entry-content"> <p>Our deprecation plan for the SHA-1 algorithm in the public Web, <a href="https://blog.mozilla.org/security/2015/10/20/continuing-to-phase-out-sha-1-certificates/">first announced in 2015</a>, is drawing to a close. Today a team of researchers from CWI Amsterdam and Google revealed <a href="https://security.googleblog.com/2017/02/announcing-first-sha1-collision.html">the first practical collision for SHA-1</a>, affirming the insecurity of the algorithm and reinforcing our judgment that it must be retired from security use on the Web.</p> <p>As <a href="https://blog.mozilla.org/security/2016/10/18/phasing-out-sha-1-on-the-public-web/">announced last fall</a>, we’ve been disabling SHA-1 for increasing numbers of Firefox users since the release of Firefox 51 using a gradual phase-in technique. Tomorrow, this deprecation policy will reach all Firefox users. It is enabled by default in Firefox 52.</p> <p>Phasing out SHA-1 in Firefox will affect people accessing websites that have not yet migrated to SHA-2 certificates, <a href="https://mzl.la/2lKDWvY">well under 0.1% of Web traffic</a>. In parallel to phasing out insecure cryptography from Firefox, we will continue our outreach efforts to help website operators use modern and secure HTTPS.</p> <p>Users should always make sure to update to the latest version of Firefox for the most-recent security updates and features by going to <a href="https://www.mozilla.org/firefox">https://www.mozilla.org/firefox</a>.</p> <p>Questions about Mozilla policies related to SHA-1 based certificates should be directed to the<a href="https://groups.google.com/forum/#%21forum/mozilla.dev.security.policy"> mozilla.dev.security.policy</a> forum.</p> </div> <footer class="entry-tags"> <p><b>Tags:</b> <a href="https://blog.mozilla.org/security/tag/tls/" rel="tag">TLS</a></p> </footer> <footer class="fx-footer"> <h4>Browse fast. Browse free.</h4> <p><a href="https://www.mozilla.org/firefox/new/?utm_source=blog.mozilla.org&utm_campaign=firefox_frontier&utm_medium=referral" rel="external" class="button button-product">Download Firefox</a></p> </footer> </article><!-- #post --> </div> <nav id="adjacent-posts" class="section nav-paging"> <div class="content"> <p class="nav-paging-prev" role="navigation"> <a href="https://blog.mozilla.org/security/2017/01/29/mozilla-security-bytes-episode-1-csp/"> <span class="label">Previous article</span> <strong class="entry-title">Mozilla Security Bytes, ep. 1: Content Security Policy</strong> <time class="date" datetime="2017-01-29T08:45:20-08:00">January 29, 2017</time> <svg class="arrow-left" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 23.62 43"><defs><style>.cls-1{fill:none;stroke:#000;stroke-linecap:round;stroke-miterlimit:10;stroke-width:3px;}</style></defs><polyline class="cls-1" points="22.12 1.5 2.12 21.5 22.12 41.5"/></svg> </a> </p> <p class="nav-paging-next" role="navigation"> <a href="https://blog.mozilla.org/security/2017/04/04/mozilla-releases-version-2-4-ca-certificate-policy/"> <span class="label">Next article</span> <strong class="entry-title">Mozilla Releases Version 2.4 of CA Certificate Policy</strong> <time class="date" datetime="2017-04-04T13:10:17-07:00">April 4, 2017</time> <svg class="arrow-right" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 23.62 43"><defs><style>.cls-1{fill:none;stroke:#000;stroke-linecap:round;stroke-miterlimit:10;stroke-width:3px;}</style></defs><polyline class="cls-1" points="1.5 1.5 21.5 21.5 1.5 41.5"/></svg> </a> </p> </div> </nav> <aside id="related-posts" class="section"> <div class="content"> <div class="in-category"> <h4 class="module-title">More articles in “CA Program”</h4> <ul class="cat-posts"> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2023/09/13/version-2-9-of-the-mozilla-root-store-policy/">Version 2.9 of the Mozilla Root Store Policy</a></h5> <time class="date" datetime="2023-09-13T10:56:32-07:00">September 13, 2023</time> </li> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2022/05/23/upgrading-mrsp-to-v-2-8/">Upgrading Mozilla’s Root Store Policy to Version 2.8</a></h5> <time class="date" datetime="2022-05-23T00:01:47-07:00">May 23, 2022</time> </li> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2022/05/16/revocation-reason-codes-for-tls-server-certificates/">Revocation Reason Codes for TLS Server Certificates</a></h5> <time class="date" datetime="2022-05-16T08:00:08-07:00">May 16, 2022</time> </li> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2021/12/09/improved-quality-of-intermediate-certificates-with-enhanced-oversight-and-automation/">Improving the Quality of Publicly Trusted Intermediate CA Certificates with Enhanced Oversight and Automation</a></h5> <time class="date" datetime="2021-12-09T08:00:50-08:00">December 9, 2021</time> </li> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2021/04/26/mrsp-v-2-7-1/">Upgrading Mozilla’s Root Store Policy to Version 2.7.1</a></h5> <time class="date" datetime="2021-04-26T12:00:45-07:00">April 26, 2021</time> </li> </ul> </div> <div class="popular"> <h4 class="module-title">Recent articles</h4> <ul class="recent-posts"> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2024/10/11/behind-the-scenes-fixing-an-in-the-wild-firefox-exploit/">Behind the Scenes: Fixing an In-the-Wild Firefox Exploit</a></h5> <time class="date" datetime="2024-10-11T05:14:24-07:00">October 11, 2024</time> </li> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2024/06/05/firefox-will-upgrade-more-mixed-content-in-version-127/">Firefox will upgrade more Mixed Content in Version 127</a></h5> <time class="date" datetime="2024-06-05T06:05:31-07:00">June 5, 2024</time> </li> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2024/04/04/rapidly-leveling-up-firefox-security/">Rapidly Leveling up Firefox Security</a></h5> <time class="date" datetime="2024-04-04T12:27:41-07:00">April 4, 2024</time> </li> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2023/12/06/mozilla-vpn-security-audit-2023/">Mozilla VPN Security Audit 2023</a></h5> <time class="date" datetime="2023-12-06T09:00:37-08:00">December 6, 2023</time> </li> <li> <h5 class="entry-title"><a href="https://blog.mozilla.org/security/2023/09/13/version-2-9-of-the-mozilla-root-store-policy/">Version 2.9 of the Mozilla Root Store Policy</a></h5> <time class="date" datetime="2023-09-13T10:56:32-07:00">September 13, 2023</time> </li> </ul> </div> </div> </aside> <aside id="newsletter-subscribe" class="section newsletter-firefox"> <form id="newsletter_form" class="content newsletter_form" name="newsletter_form" action="https://www.mozilla.org/en-US/newsletter/" method="post" data-blog="Mozilla Security Blog"> <input type="hidden" id="newsletters" name="newsletters" value="mozilla-and-you"> <input type="hidden" id="source_url" name="source_url" value="https://blog.mozilla.org/security/2017/02/23/the-end-of-sha-1-on-the-public-web"> <div class="form-title"> <h3>Keep up with<br> all things Firefox.</h3> </div> <div id="form-contents" class="form-contents"> <div id="newsletter_errors" class="newsletter_errors"></div> <div class="field field-email"> <label for="email">Your e-mail address</label> <input type="email" id="email" name="email" required placeholder="yourname@example.com" size="30"> </div> <div class="form-details"> <div class="field field-country"> <label for="country">Country</label> <select id="country" name="country" required="required"> <option value="" selected="selected">- select -</option> <option value="af">Afghanistan</option> <option value="qz">Akrotiri</option> <option value="al">Albania</option> <option value="dz">Algeria</option> <option value="as">American Samoa</option> <option value="ad">Andorra</option> <option value="ao">Angola</option> <option value="ai">Anguilla</option> <option value="aq">Antarctica</option> <option value="ag">Antigua and Barbuda</option> <option value="ar">Argentina</option> <option value="am">Armenia</option> <option value="aw">Aruba</option> <option value="xa">Ashmore and Cartier Islands</option> <option value="au">Australia</option> <option value="at">Austria</option> <option value="az">Azerbaijan</option> <option value="bs">Bahamas, The</option> <option value="bh">Bahrain</option> <option value="xb">Baker Island</option> <option value="bd">Bangladesh</option> <option value="bb">Barbados</option> <option value="qs">Bassas da India</option> <option value="by">Belarus</option> <option value="be">Belgium</option> <option value="bz">Belize</option> <option value="bj">Benin</option> <option value="bm">Bermuda</option> <option value="bt">Bhutan</option> <option value="bo">Bolivia</option> <option value="bq">Bonaire, Sint Eustatius, and Saba</option> <option value="ba">Bosnia and Herzegovina</option> <option value="bw">Botswana</option> <option value="bv">Bouvet Island</option> <option value="br">Brazil</option> <option value="io">British Indian Ocean Territory</option> <option value="bn">Brunei</option> <option value="bg">Bulgaria</option> <option value="bf">Burkina Faso</option> <option value="mm">Burma</option> <option value="bi">Burundi</option> <option value="cv">Cabo Verde</option> <option value="kh">Cambodia</option> <option value="cm">Cameroon</option> <option value="ca">Canada</option> <option value="ky">Cayman Islands</option> <option value="cf">Central African Republic</option> <option value="td">Chad</option> <option value="cl">Chile</option> <option value="cn">China</option> <option value="cx">Christmas Island</option> <option value="cp">Clipperton Island</option> <option value="cc">Cocos (Keeling) Islands</option> <option value="co">Colombia</option> <option value="km">Comoros</option> <option value="cg">Congo (Brazzaville)</option> <option value="cd">Congo (Kinshasa)</option> <option value="ck">Cook Islands</option> <option value="xc">Coral Sea Islands</option> <option value="cr">Costa Rica</option> <option value="hr">Croatia</option> <option value="cu">Cuba</option> <option value="cw">Curaçao</option> <option value="cy">Cyprus</option> <option value="cz">Czech Republic</option> <option value="ci">Côte d’Ivoire</option> <option value="dk">Denmark</option> <option value="xd">Dhekelia</option> <option value="dg">Diego Garcia</option> <option value="dj">Djibouti</option> <option value="dm">Dominica</option> <option value="do">Dominican Republic</option> <option value="ec">Ecuador</option> <option value="eg">Egypt</option> <option value="sv">El Salvador</option> <option value="gq">Equatorial Guinea</option> <option value="er">Eritrea</option> <option value="ee">Estonia</option> <option value="et">Ethiopia</option> <option value="xe">Europa Island</option> <option value="fk">Falkland Islands (Islas Malvinas)</option> <option value="fo">Faroe Islands</option> <option value="fj">Fiji</option> <option value="fi">Finland</option> <option value="fr">France</option> <option value="gf">French Guiana</option> <option value="pf">French Polynesia</option> <option value="tf">French Southern and Antarctic Lands</option> <option value="ga">Gabon</option> <option value="gm">Gambia, The</option> <option value="xg">Gaza Strip</option> <option value="ge">Georgia</option> <option value="de">Germany</option> <option value="gh">Ghana</option> <option value="gi">Gibraltar</option> <option value="qx">Glorioso Islands</option> <option value="gr">Greece</option> <option value="gl">Greenland</option> <option value="gd">Grenada</option> <option value="gp">Guadeloupe</option> <option value="gu">Guam</option> <option value="gt">Guatemala</option> <option value="gg">Guernsey</option> <option value="gn">Guinea</option> <option value="gw">Guinea-Bissau</option> <option value="gy">Guyana</option> <option value="ht">Haiti</option> <option value="hm">Heard Island and McDonald Islands</option> <option value="hn">Honduras</option> <option value="hk">Hong Kong</option> <option value="xh">Howland Island</option> <option value="hu">Hungary</option> <option value="is">Iceland</option> <option value="in">India</option> <option value="id">Indonesia</option> <option value="ir">Iran</option> <option value="iq">Iraq</option> <option value="ie">Ireland</option> <option value="im">Isle of Man</option> <option value="il">Israel</option> <option value="it">Italy</option> <option value="jm">Jamaica</option> <option value="xj">Jan Mayen</option> <option value="jp">Japan</option> <option value="xq">Jarvis Island</option> <option value="je">Jersey</option> <option value="xu">Johnston Atoll</option> <option value="jo">Jordan</option> <option value="qu">Juan de Nova Island</option> <option value="kz">Kazakhstan</option> <option value="ke">Kenya</option> <option value="xm">Kingman Reef</option> <option value="ki">Kiribati</option> <option value="kp">Korea, North</option> <option value="kr">Korea, South</option> <option value="xk">Kosovo</option> <option value="kw">Kuwait</option> <option value="kg">Kyrgyzstan</option> <option value="la">Laos</option> <option value="lv">Latvia</option> <option value="lb">Lebanon</option> <option value="ls">Lesotho</option> <option value="lr">Liberia</option> <option value="ly">Libya</option> <option value="li">Liechtenstein</option> <option value="lt">Lithuania</option> <option value="lu">Luxembourg</option> <option value="mo">Macau</option> <option value="mk">Macedonia</option> <option value="mg">Madagascar</option> <option value="mw">Malawi</option> <option value="my">Malaysia</option> <option value="mv">Maldives</option> <option value="ml">Mali</option> <option value="mt">Malta</option> <option value="mh">Marshall Islands</option> <option value="mq">Martinique</option> <option value="mr">Mauritania</option> <option value="mu">Mauritius</option> <option value="yt">Mayotte</option> <option value="mx">Mexico</option> <option value="fm">Micronesia, Federated States of</option> <option value="qm">Midway Islands</option> <option value="md">Moldova</option> <option value="mc">Monaco</option> <option value="mn">Mongolia</option> <option value="me">Montenegro</option> <option value="ms">Montserrat</option> <option value="ma">Morocco</option> <option value="mz">Mozambique</option> <option value="na">Namibia</option> <option value="nr">Nauru</option> <option value="xv">Navassa Island</option> <option value="np">Nepal</option> <option value="nl">Netherlands</option> <option value="nc">New Caledonia</option> <option value="nz">New Zealand</option> <option value="ni">Nicaragua</option> <option value="ne">Niger</option> <option value="ng">Nigeria</option> <option value="nu">Niue</option> <option value="nf">Norfolk Island</option> <option value="mp">Northern Mariana Islands</option> <option value="no">Norway</option> <option value="om">Oman</option> <option value="pk">Pakistan</option> <option value="pw">Palau</option> <option value="xl">Palmyra Atoll</option> <option value="pa">Panama</option> <option value="pg">Papua New Guinea</option> <option value="xp">Paracel Islands</option> <option value="py">Paraguay</option> <option value="pe">Peru</option> <option value="ph">Philippines</option> <option value="pn">Pitcairn Islands</option> <option value="pl">Poland</option> <option value="pt">Portugal</option> <option value="pr">Puerto Rico</option> <option value="qa">Qatar</option> <option value="re">Reunion</option> <option value="ro">Romania</option> <option value="ru">Russia</option> <option value="rw">Rwanda</option> <option value="bl">Saint Barthelemy</option> <option value="sh">Saint Helena, Ascension, and Tristan da Cunha</option> <option value="kn">Saint Kitts and Nevis</option> <option value="lc">Saint Lucia</option> <option value="mf">Saint Martin</option> <option value="pm">Saint Pierre and Miquelon</option> <option value="vc">Saint Vincent and the Grenadines</option> <option value="ws">Samoa</option> <option value="sm">San Marino</option> <option value="st">Sao Tome and Principe</option> <option value="sa">Saudi Arabia</option> <option value="sn">Senegal</option> <option value="rs">Serbia</option> <option value="sc">Seychelles</option> <option value="sl">Sierra Leone</option> <option value="sg">Singapore</option> <option value="sx">Sint Maarten</option> <option value="sk">Slovakia</option> <option value="si">Slovenia</option> <option value="sb">Solomon Islands</option> <option value="so">Somalia</option> <option value="za">South Africa</option> <option value="gs">South Georgia and South Sandwich Islands</option> <option value="ss">South Sudan</option> <option value="es">Spain</option> <option value="xs">Spratly Islands</option> <option value="lk">Sri Lanka</option> <option value="sd">Sudan</option> <option value="sr">Suriname</option> <option value="xr">Svalbard</option> <option value="sz">Swaziland</option> <option value="se">Sweden</option> <option value="ch">Switzerland</option> <option value="sy">Syria</option> <option value="tw">Taiwan</option> <option value="tj">Tajikistan</option> <option value="tz">Tanzania</option> <option value="th">Thailand</option> <option value="tl">Timor-Leste</option> <option value="tg">Togo</option> <option value="tk">Tokelau</option> <option value="to">Tonga</option> <option value="tt">Trinidad and Tobago</option> <option value="xt">Tromelin Island</option> <option value="tn">Tunisia</option> <option value="tr">Turkey</option> <option value="tm">Turkmenistan</option> <option value="tc">Turks and Caicos Islands</option> <option value="tv">Tuvalu</option> <option value="ug">Uganda</option> <option value="ua">Ukraine</option> <option value="ae">United Arab Emirates</option> <option value="gb">United Kingdom</option> <option value="us">United States</option> <option value="uy">Uruguay</option> <option value="uz">Uzbekistan</option> <option value="vu">Vanuatu</option> <option value="va">Vatican City</option> <option value="ve">Venezuela</option> <option value="vn">Vietnam</option> <option value="vg">Virgin Islands, British</option> <option value="vi">Virgin Islands, U.S.</option> <option value="qw">Wake Island</option> <option value="wf">Wallis and Futuna</option> <option value="xw">West Bank</option> <option value="eh">Western Sahara</option> <option value="ye">Yemen</option> <option value="zm">Zambia</option> <option value="zw">Zimbabwe</option> </select> </div> <div class="field field-language"> <label for="lang">Language</label> <select id="lang" name="lang" required="required"> <option value="id">Bahasa Indonesia</option> <option value="de">Deutsch</option> <option value="en" selected="selected">English</option> <option value="es">Español</option> <option value="fr">Français</option> <option value="pl">Polski</option> <option value="pt">Português</option> <option value="ru">Русский</option> <option value="zh-TW">正體中文</option> </select> </div> <div class="field field-format"> <label for="format-h"><input checked="checked" id="format-h" name="fmt" value="H" type="radio"> HTML</label> <label for="format-t"><input id="format-t" name="fmt" value="T" type="radio"> Text</label> </div> <div class="field field-privacy"> <label for="privacy"> <input type="checkbox" id="privacy" name="privacy" required> I’m okay with Mozilla handling my info as explained in this <a href="https://www.mozilla.org/privacy/">Privacy Policy</a>. </label> </div> </div> <div class="form-submit"> <button id="newsletter_submit" type="submit" class="form-button button-light">Sign up now</button> <p class="form-details promise"> <small>We will only send you Mozilla-related information.</small> </p> </div> </div> <div id="newsletter_thanks" class="thanks"> <h2>Thanks!</h2> <p> If you haven’t previously confirmed a subscription to a Mozilla-related newsletter you may have to do so. Please check your inbox or your spam filter for an e-mail from us. </p> </div> </form> </aside> </main> <aside id="sidebar" class="section widgets can-stick"> <div class="content"> </div> </aside> </div><!-- /.site-wrap --> <footer id="site-info" class="section"> <div class="content"> <nav class="primary"> <div class="logo"> <a href="https://www.mozilla.org/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="Mozilla">Mozilla</a> </div> <section class="mozilla"> <h5><a href="https://www.mozilla.org/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="Mozilla">Mozilla</a></h5> <ul class="mozilla-links"> <li><a href="https://www.mozilla.org/about/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="About">About</a></li> <li><a href="https://www.mozilla.org/contact/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="Contact Us">Contact Us</a></li> <li><a href="https://donate.mozilla.org/?presets=50,30,20,10&amount=30&currency=usd&utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" class="donate" data-link-type="footer" data-link-name="Donate">Donate</a></li> <li> <ul class="social-links"> <li><a class="twitter" href="https://twitter.com/mozilla" data-link-type="footer" data-link-name="Twitter (@mozilla)">Twitter<span> (@mozilla)</span></a></li> <li><a class="instagram" href="https://www.instagram.com/mozillagram/" data-link-type="footer" data-link-name="Instagram (@mozillagram)">Instagram<span> (@mozillagram)</span></a></li> </ul> </li> </ul> </section> <section class="firefox"> <h5><a href="https://www.mozilla.org/firefox/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="Mozilla">Firefox</a></h5> <ul class="firefox-links"> <li><a href="https://www.mozilla.org/firefox/new/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="Download Firefox">Download Firefox</a></li> <li><a href="https://www.mozilla.org/firefox/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="Desktop">Desktop</a></li> <li><a href="https://www.mozilla.org/firefox/mobile/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="Mobile">Mobile</a></li> <li><a href="https://www.mozilla.org/firefox/features/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="Features">Features</a></li> <li><a href="https://www.mozilla.org/firefox/channel/desktop/?utm_source=blog.mozilla.org&utm_campaign=footer&utm_medium=referral" data-link-type="footer" data-link-name="Beta, Nightly, Developer Edition">Beta, Nightly, Developer Edition</a></li> <li> <ul class="social-links"> <li><a class="twitter" href="https://twitter.com/firefox" data-link-type="footer" data-link-name="Twitter (@firefox)">Twitter<span> (@firefox)</span></a></li> <li><a class="youtube" href="https://www.youtube.com/firefoxchannel" data-link-type="footer" data-link-name="YouTube (firefoxchannel)">YouTube<span> (firefoxchannel)</span></a></li> </ul> </li> </ul> </section> </nav> <nav class="secondary"> <div class="small-links"> <ul> <li><a rel="nofollow" href="https://www.mozilla.org/privacy/" data-link-type="footer" data-link-name="Privacy">Website Privacy Notice</a></li> <li><a rel="nofollow" href="https://www.mozilla.org/privacy/websites/#cookies" data-link-type="footer" data-link-name="Cookies">Cookies</a></li> <li><a rel="nofollow" href="https://www.mozilla.org/about/legal/" data-link-type="footer" data-link-name="Legal">Legal</a></li> </ul> <p class="license"> Visit Mozilla Corporation’s not-for-profit parent, the <a href="https://foundation.mozilla.org" data-link-type="footer" data-link-name="Mozilla Foundation">Mozilla Foundation</a>. </p> <p class="license"> Portions of this content are ©1998-2024 by individual contributors. Content available under a <a href="https://www.mozilla.org/foundation/licensing/website-content/" rel="external license">Creative Commons license</a>. </p> </div> </nav> </div> </footer> <!--[if IE 9]> <script type="text/javascript" src="https://blog.mozilla.org/security/wp-content/themes/frontierline/js/matchMedia.js"></script> <script type="text/javascript" src="https://blog.mozilla.org/security/wp-content/themes/frontierline/js/matchMedia.addListener.js"></scrip> <![endif]--> <script type='text/javascript' src='https://blog.mozilla.org/security/wp-content/themes/frontierline/js/global.js?ver=2.2' id='global-js'></script> <script type='text/javascript' src='https://blog.mozilla.org/security/wp-content/themes/frontierline/js/basket-client.js?ver=1.2' id='basket-client-js'></script> </body> </html>