An Overview of TLS 1.3 – Faster and More Secure

By , Updated: June 5, 2017

It has been over eight years since the last encryption protocol update, but the new TLS 1.3 is now about to be finalized. The exciting part for the WordPress community and customers here at Kinsta is that TLS 1.3 includes a lot of security and performance improvements. With the HTTP/2 protocol update in late 2015, and now TLS 1.3 in 2017, encrypted connections are now more secure and faster than ever. Read more below about the changes coming with TLS 1.3 and how it can benefit you as a WordPress site owner.

'TLS 1.3: Faster, Safer, Better, Everything.' -- Filippo Valsorda Click to Tweet

What is TLS?

TLS stands for Transport Layer Security and is the successor to SSL (Secure Sockets Layer). However, both these terms are commonly thrown around a lot online and you might see them both referred to as simply SSL.  TLS provides secure communication between web browsers and servers. The connection itself is secure because symmetric cryptography is used to encrypt the data transmitted. The keys are uniquely generated for each connection and are based on a shared secret negotiated at the beginning of the session, also known as a TLS handshake. Many IP-based protocols, such as HTTPS, SMTP, POP3, FTP support TLS to encrypt data.

Web browsers utilize an SSL certificate which allows them to recognize that it belongs to a digitally signed certificate authority. Technically these are also known as TLS certificates, but most SSL providers stick with the term “SSL certificates” as this is generally more well known. SSL/TLS certificates provide the magic behind what many people simply know as the HTTPS that they see in their browser’s address bar.

https web browser address bar

TLS 1.3 vs TLS 1.2

The Internet Engineering Task Force (IETF) is the group that has been in charge of defining the TLS protocol, which has gone through many various iterations. The current version of TLS, TLS 1.2, was defined in RFC 5246 and has been in use for the past eight years by the majority of all web browsers. TLS 1.3, is still in draft (on Github), but will most likely be finalized by mid 2017. Companies such as Cloudflare are already making TLS 1.3 available to their customers. Filippo Valsorda had a great talk (see presentation below) on the differences between TLS 1.2 and TLS 1.3. In short, the major benefits of TLS 1.3 vs that of TLS 1.2 is faster speeds and improved security.

Speed Benefits of TLS 1.3

TLS and encrypted connections have always added a slight overhead when it comes to web performance. HTTP/2 definitely helped with this problem, but TLS 1.3 helps speed up encrypted connections even more. To put it simply, with TLS 1.2, two round-trips have been needed to complete the TLS handshake. With 1.3, it requires only one round-trip, which in turn cuts the encryption latency in half. This helps those encrypted connections feel just a little bit snappier than before.

tls 1.3 handshake performance

Another advantage of is that in a sense, it remembers! On sites you have previously visited, you can now send data on the first message to the server. This is called a “zero round trip.” (0-RTT). And yes, this also results in improved load time times.

Improved Security With TLS 1.3

A big problem with TLS 1.2 is that it’s often not configured properly it leaves websites vulnerable to attacks. TLS 1.3 now removes obsolete and insecure features from TLS 1.2, including the following:

  • SHA-1
  • RC4
  • DES
  • 3DES
  • MD5
  • Arbitrary Diffie-Hellman groups — CVE-2016-0701
  • EXPORT-strength ciphers – Responsible for FREAK and LogJam

Because the protocol is in a sense more simplified, this make it less likely for administrators and developers to misconfigure the protocol. Jessie Victors, a security consultant, specializing in privacy-enhancing systems and applied cryptography stated:

“I am excited for the upcoming standard. I think we will see far fewer vulnerabilities and we will be able to trust TLS far more than we have in the past.”

TLS 1.3 Browser Support

With all the being said most SSL test services on the Internet don’t support TLS 1.3 yet and neither do browsers. It will be a couple more months while the protocol is being finalized and for browsers to catch up. If you are wanting to test it, the latest dev versions of Firefox and Chrome support it, it simply isn’t enabled by default. Note: Some sites may be broken if TLS 1.3 is enabled. See the following instructions on how to enable it in your browser.

Enable TLS 1.3 in Firefox Nightly

  • Install Firefox nightly:
  • Enter “about:config” in the address bar
  • Set security.tls.version.max from 3 to 4
  • Restart the browser

mozilla firefox tls 1.3

TLS 1.3 support will be default in Firefox 52, which will be coming in 2017. They will retain an insecure fallback to TLS 1.2 until they know more about server tolerance and the 1.3 handshake.

Enable TLS 1.3 in Chrome Canary

chrome tls 1.3


Just like with HTTP/2, TLS 1.3 is another exciting protocol update that we can expect to benefit from for years to come. Not only will encrypted (HTTPS) connections become faster, but they will also be more secure. Stay tuned for more updates as it will most likely be finalized by mid 2017.