TLS 1.3 (TLS 1.3)
The Essentials
- Released in 2018 as RFC 8446
- Reduces handshake to 1 round trip (from 2 in TLS 1.2)
- Supports 0-RTT session resumption for repeat visitors
- Removes all legacy cipher suites (RC4, 3DES, CBC mode)
- Forward secrecy is mandatory, not optional
Why You Should Care About TLS 1.3
TLS 1.3 is a significant improvement over TLS 1.2 in both security and performance. It removed all cipher suites that had known weaknesses, including RSA key exchange, CBC mode ciphers, and SHA-1. Only modern AEAD cipher suites with forward secrecy are allowed, which means there are fewer ways to misconfigure it insecurely.
The performance improvement from TLS 1.3 is meaningful for user experience. The one-round-trip handshake (compared to two in TLS 1.2) reduces connection setup time by roughly one network round trip, which is especially noticeable on high-latency mobile connections. The 0-RTT resumption feature allows repeat visitors to send data immediately, though it has replay attack considerations.
TLS 1.3 is broadly supported. Enabling it alongside a well-configured TLS 1.2 policy is a common compatibility choice, but test required clients, TLS inspection devices, and 0-RTT behavior. Protocol support alone does not make the rest of the deployment secure.
How to Verify
Run an SSL checker to see if your server supports TLS 1.3. The tool will list all supported protocol versions. If TLS 1.3 is not listed, check your web server and OpenSSL version - you may need to update to a version that supports it.
Check SSL CertificateLessons From the Field
TLS 1.3 reduces a full handshake by one network round trip compared with a typical TLS 1.2 full handshake. The measured benefit depends on network latency, connection reuse, protocol negotiation, and whether 0-RTT is safely enabled for eligible requests.