butterfly/kb
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
9d19eebc64
kb/data/developer.mozilla.org/en-US/docs/Glossary/TLS-0.md

187 lines
11 KiB
Markdown
Raw Blame History

---
title: "Transport Layer Security (TLS) - Glossary | MDN"
chunk: 1/3
source: "https://developer.mozilla.org/en-US/docs/Glossary/TLS"
category: "reference"
tags: "web, html, css, javascript, documentation"
date_saved: "2026-05-05T05:46:47.563480+00:00"
instance: "kb-cron"
---
* [Skip to main content](https://developer.mozilla.org/en-US/docs/Glossary/TLS#content)
* [Skip to search](https://developer.mozilla.org/en-US/docs/Glossary/TLS#search)
[ MDN ](https://developer.mozilla.org/en-US/)
HTML
[HTML: Markup language](https://developer.mozilla.org/en-US/docs/Web/HTML)
HTML reference
* [Elements](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements)
* [Global attributes](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Global_attributes)
* [Attributes](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Attributes)
* [See all…](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference "See all HTML references")
HTML guides
* [Responsive images](https://developer.mozilla.org/en-US/docs/Web/HTML/Guides/Responsive_images)
* [HTML cheatsheet](https://developer.mozilla.org/en-US/docs/Web/HTML/Guides/Cheatsheet)
* [Date & time formats](https://developer.mozilla.org/en-US/docs/Web/HTML/Guides/Date_and_time_formats)
* [See all…](https://developer.mozilla.org/en-US/docs/Web/HTML/Guides "See all HTML guides")
Markup languages
* [SVG](https://developer.mozilla.org/en-US/docs/Web/SVG)
* [MathML](https://developer.mozilla.org/en-US/docs/Web/MathML)
* [XML](https://developer.mozilla.org/en-US/docs/Web/XML)
CSS
[CSS: Styling language](https://developer.mozilla.org/en-US/docs/Web/CSS)
CSS reference
* [Properties](https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Properties)
* [Selectors](https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Selectors)
* [At-rules](https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/At-rules)
* [Values](https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Values)
* [See all…](https://developer.mozilla.org/en-US/docs/Web/CSS/Reference "See all CSS references")
CSS guides
* [Box model](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Box_model/Introduction)
* [Animations](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Animations/Using)
* [Flexbox](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Flexible_box_layout/Basic_concepts)
* [Colors](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Colors/Applying_color)
* [See all…](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides "See all CSS guides")
Layout cookbook
* [Column layouts](https://developer.mozilla.org/en-US/docs/Web/CSS/How_to/Layout_cookbook/Column_layouts)
* [Centering an element](https://developer.mozilla.org/en-US/docs/Web/CSS/How_to/Layout_cookbook/Center_an_element)
* [Card component](https://developer.mozilla.org/en-US/docs/Web/CSS/How_to/Layout_cookbook/Card)
* [See all…](https://developer.mozilla.org/en-US/docs/Web/CSS/How_to/Layout_cookbook)
JavaScriptJS
[JavaScript: Scripting language](https://developer.mozilla.org/en-US/docs/Web/JavaScript)
JS reference
* [Standard built-in objects](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects)
* [Expressions & operators](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators)
* [Statements & declarations](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements)
* [Functions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions)
* [See all…](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference "See all JavaScript references")
JS guides
* [Control flow & error handing](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Control_flow_and_error_handling)
* [Loops and iteration](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Loops_and_iteration)
* [Working with objects](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Working_with_objects)
* [Using classes](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Using_classes)
* [See all…](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide "See all JavaScript guides")
Web APIs
[Web APIs: Programming interfaces](https://developer.mozilla.org/en-US/docs/Web/API)
Web API reference
* [File system API](https://developer.mozilla.org/en-US/docs/Web/API/File_System_API)
* [Fetch API](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API)
* [Geolocation API](https://developer.mozilla.org/en-US/docs/Web/API/Geolocation_API)
* [HTML DOM API](https://developer.mozilla.org/en-US/docs/Web/API/HTML_DOM_API)
* [Push API](https://developer.mozilla.org/en-US/docs/Web/API/Push_API)
* [Service worker API](https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API)
* [See all…](https://developer.mozilla.org/en-US/docs/Web/API "See all Web API guides")
Web API guides
* [Using the Web animation API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Animations_API/Using_the_Web_Animations_API)
* [Using the Fetch API](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch)
* [Working with the History API](https://developer.mozilla.org/en-US/docs/Web/API/History_API/Working_with_the_History_API)
* [Using the Web speech API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Speech_API/Using_the_Web_Speech_API)
* [Using web workers](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Using_web_workers)
All
[All web technology](https://developer.mozilla.org/en-US/docs/Web)
Technologies
* [Accessibility](https://developer.mozilla.org/en-US/docs/Web/Accessibility)
* [HTTP](https://developer.mozilla.org/en-US/docs/Web/HTTP)
* [URI](https://developer.mozilla.org/en-US/docs/Web/URI)
* [Web extensions](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions)
* [WebAssembly](https://developer.mozilla.org/en-US/docs/WebAssembly)
* [WebDriver](https://developer.mozilla.org/en-US/docs/Web/WebDriver)
* [See all…](https://developer.mozilla.org/en-US/docs/Web "See all web technology references")
Topics
* [Media](https://developer.mozilla.org/en-US/docs/Web/Media)
* [Performance](https://developer.mozilla.org/en-US/docs/Web/Performance)
* [Privacy](https://developer.mozilla.org/en-US/docs/Web/Privacy)
* [Security](https://developer.mozilla.org/en-US/docs/Web/Security)
* [Progressive web apps](https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps)
Learn
[Learn web development](https://developer.mozilla.org/en-US/docs/Learn_web_development)
Frontend developer course
* [Getting started modules](https://developer.mozilla.org/en-US/docs/Learn_web_development/Getting_started)
* [Core modules](https://developer.mozilla.org/en-US/docs/Learn_web_development/Core)
* [MDN Curriculum](https://developer.mozilla.org/en-US/curriculum/)
* [Check out the video course from Scrimba, our partner](https://scrimba.com/frontend-path-c0j?via=mdn-learn-navbar)
Learn HTML
* [Structuring content with HTML module](https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/Structuring_content)
Learn CSS
* [CSS styling basics module](https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/Styling_basics)
* [CSS layout module](https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/CSS_layout)
Learn JavaScript
* [Dynamic scripting with JavaScript module](https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/Scripting)
Tools
Discover our tools
* [Playground](https://developer.mozilla.org/en-US/play)
* [HTTP Observatory](https://developer.mozilla.org/en-US/observatory)
* [Border-image generator](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Backgrounds_and_borders/Border-image_generator)
* [Border-radius generator](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Backgrounds_and_borders/Border-radius_generator)
* [Box-shadow generator](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Backgrounds_and_borders/Box-shadow_generator)
* [Color format converter](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Colors/Color_format_converter)
* [Color mixer](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Colors/Color_mixer)
* [Shape generator](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Shapes/Shape_generator)
About
Get to know MDN better
* [About MDN](https://developer.mozilla.org/en-US/about)
* [Advertise with us](https://developer.mozilla.org/en-US/advertising)
* [Community](https://developer.mozilla.org/en-US/community)
* [MDN on GitHub](https://github.com/mdn)
[Blog](https://developer.mozilla.org/en-US/blog/)
1. [Glossary](https://developer.mozilla.org/en-US/docs/Glossary)
2. [Transport Layer Security (TLS)](https://developer.mozilla.org/en-US/docs/Glossary/TLS)
# Transport Layer Security (TLS)
**Transport Layer Security (TLS)** , formerly known as [Secure Sockets Layer (SSL)](https://developer.mozilla.org/en-US/docs/Glossary/SSL), is a [protocol](https://developer.mozilla.org/en-US/docs/Glossary/Protocol) used by applications to communicate securely across a network, preventing tampering with and eavesdropping on email, web browsing, messaging, and other protocols. Both TLS and SSL are client / server protocols that ensure communication privacy by using cryptographic protocols to provide security over a network. When a server and client communicate using TLS, it ensures that no third party can eavesdrop or tamper with any message.
All modern browsers support the TLS protocol, requiring the server to provide a valid [digital certificate](https://developer.mozilla.org/en-US/docs/Glossary/Digital_certificate) confirming its identity in order to establish a secure connection. It is possible for both the client and server to mutually authenticate each other, if both parties provide their own individual digital certificates.
**Note:** All major browsers began removing support for TLS 1.0 and 1.1 in early 2020; you'll need to make sure your web server supports TLS 1.2 or 1.3 going forward. From version 74 onwards, Firefox will return a [Secure Connection Failed](https://support.mozilla.org/en-US/kb/secure-connection-failed-firefox-did-not-connect) error when connecting to servers using the older TLS versions ([Firefox bug 1606734](https://bugzil.la/1606734)).
## In this article
* [See also](https://developer.mozilla.org/en-US/docs/Glossary/TLS#see_also)
## [See also](https://developer.mozilla.org/en-US/docs/Glossary/TLS#see_also)
* [Transport Layer Security](https://en.wikipedia.org/wiki/Transport_Layer_Security) (Wikipedia)
* [RFC 8446](https://datatracker.ietf.org/doc/html/rfc8446) (The Transport Layer Security Protocol, Version 1.3)
* [RFC 5246](https://datatracker.ietf.org/doc/html/rfc5246) (The Transport Layer Security Protocol, Version 1.2)
* [Transport Layer Security](https://developer.mozilla.org/en-US/docs/Web/Security/Defenses/Transport_Layer_Security)
* [Transport Layer Security Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Transport_Layer_Security_Cheat_Sheet.html) (OWASP)
* Related glossary terms:
* [HTTPS](https://developer.mozilla.org/en-US/docs/Glossary/HTTPS)
* [SSL](https://developer.mozilla.org/en-US/docs/Glossary/SSL)
Reference in New Issue View Git Blame Copy Permalink