Introducing TLS 1.3

by Nick Sullivan

CloudFlare is turbocharging the encrypted internet
The encrypted Internet is about to become a whole lot snappier. When it comes to browsing, we’ve been driving around in a beat-up car from the 90s for a while. Little does anyone know, we’re all about to trade in our station wagons for a smoking new sports car. The reason for this speed boost is TLS 1.3, a new encryption protocol that improves both speed and security for Internet users everywhere. As of today, TLS 1.3 is available to all CloudFlare customers.

The Encrypted Internet

Many of the major web properties you visit are encrypted, which is indicated by the padlock icon and the presence of “https” instead of “http” in the address bar. The “s” stands for secure. When you connect to an HTTPS site, the communication between you and the website is encrypted, which makes browsing the web dramatically more secure, protecting your communication from prying eyes and the injection of malicious code. HTTPS is not only used by websites, it also secures the majority of APIs and mobile application backends.

The underlying technology that enables secure communication on the Internet is a protocol called Transport Layer Security (TLS). TLS is an evolution of Secure Sockets Layer (SSL), a protocol developed by Netscape in the 1990s. The Internet Engineering Task Force (IETF), a standards body, has been in charge of defining the protocol, which has gone through several iterations. The last version, TLS 1.2, was standardized in 2008 and is currently supported by the majority of browsers and HTTPS-enabled web services.

TLS 1.2 can be secure when configured correctly, but its age has begun to show. In the last few years, several high-profile attacks have been published that revealed flaws in the protocol. Eight years is a long time in computer security, so the IETF have been working on a new version of the protocol, TLS 1.3, which should be finalized by the end of 2016.

TLS 1.3 is a major overhaul and has two main advantages over previous versions:

  • Enhanced security
  • Improved speed

Enhanced Security

Most of the attacks on TLS from the last few years targeted vestigial pieces of the protocol left around from the 90s. TLS 1.2 is highly configurable, and vulnerable sites simply failed to disable the older features in hopes of being compatible with old browsers.

TLS 1.3 embraces the “less is more” philosophy, removing support for older broken forms of cryptography. That means you can’t turn on the potentially vulnerable stuff, even if you try. The list of TLS 1.2 features that have been removed is extensive, and most of the exiled features have been associated with high profile attacks. These include:

CC 2.0 Generic Aqua Mechanical

TLS 1.3 removes the “bad crypto smell” of these legacy features, making it less likely that attacks on previous versions of the protocol will affect TLS 1.3. This streamlining also makes TLS 1.3 much simpler to configure for server operators. A secondary side effect of the update is that the protocol can be made much faster, resulting in a better web browsing experience.

Improved Speed

Fast page load times are critical to the success of web services. Amazon famously found that every additional 100ms of page load time decreases sales by 1%. A major component of page load time is latency: the time it takes to send data between the browser and the web server.

The impact of latency is especially noticeable for:

a) users on mobile devices

b) users that geographically far away from the server

Originally published at on September 20, 2016.