TLS 1.3

In August 2018, the Internet Engineering Task Force (IETF) approved the 1.3 version of TLS, a more secure and more efficient version. It gives a specific response to vulnerabilities that have appeared in recent years. More so, TLS 1.3 promises reduced connection latency thanks to less round-trips and the 0-RTT option.

Here is all you need to know about one of the most important changes of the web at the moment. What are the differences with older versions? How is the TLS 1.3 version better than TLS 1.2? What does this actually mean for you and your users?

TLS 1.3 = better performance 

TLS 1.3 is the promise of a secure, more efficient website, thanks to a limited number of exchanges between the server and the customer.

Indeed, the number of round-trips between the server and the client is a factor that may limit the performance of the protocol. The TLS 1.3 connection setup requires only one round-trip (versus two for TLS 1.2).

TLS 1.2 vs TLS 1.3
Source : Kinsta

0-RTT: what makes TLS 1.3 perform better

TLS 1.3 also includes an option called 0-RTT (zero round-trip) which allows you to go back to websites you have previously visited without renegotiating encryption.

Thus, during the very first connection of a client to the server, there is complete negotiation. The client keeps a cached message, Server Config (SCFG). All subsequent connections will use it to get derived keys and start exchanging data immediately.

The client may send data to the server on the first message to the server.

0 rtt vs 1 rtt
Source : Key CDN

Result: With TLS 1.3, secure web pages load faster! 

Major security differences between TLS 1.2 and TLS 1.3 

10 years ago, TLS 1.2 focused on cryptographic improvements, especially in hashing. In recent years, security breaches such as Crime, Drown, or Lucky 13 appeared. TLS 1.3 is a solution to the latter.

Alternatives and  more limited primitives

One of the main weaknesses of TLS 1.2 is that it uses a fairly large variety of cryptographic algorithms. Amongst them, vulnerable primitives contribute to weak TLS configurations. Too often misconfigured, because of this variety, TLS 1.2 leaves websites vulnerable to security breaches.

TLS 1.3 abandons the obsolete and unsecured features of TLS 1.2 (such as SHA-1, RC4, DES, 3DES, AES-CBC, MD5) for more secure alternatives (such as ChaCha20, Poly1305, Ed25519, x448 and x25519). The choice of primitives is now more limited and makes TLS configuration easier.

User privacy better protected

In previous versions of TLS, the handshake ran in clear, which could result in information leakage (including client and server identities).
Furthermore, as Mozilla explains, "many network middleboxes (intermediate systems for web traffic) used this information to enforce network policies and failed if the information wasn't where they expected it. This could break the protocol when new features were introduced. TLS 1.3 encrypts most of the handshake, which provides better privacy and, gives us more freedom to evolve the protocol in the future. "

Where are we with the implementation of TLS 1.3?

TLS 1.2 is currently the most used version of the protocol (94% of websites).

However, the new version of the protocol is already being deployed: Firefox and Chrome have already implemented a first draft of the TLS 1.3 specification, while Google and Facebook are already running TLS 1.3 on their servers.

Mozilla telemetry data shows that 5% of connections with Firefox are in TLS 1.3.
What about Fasterize? We are proud to announce that we are already offering one of the first CDN to implement TLS 1.3 with the 0-RTT option!

Interested in web performance? Also read our article
"4 crucial speed boosts for your HTTPS-enabled web site"
Read the article