TLS 1.2 vs TLS 1.3: Performance, Security, and Compatibility
TLS 1.3 brought major improvements over TLS 1.2 with a faster handshake, stronger cipher suites, and removal of legacy vulnerabilities. This guide compares both versions and covers the deprecation of TLS 1.0 and 1.1.
Side-by-Side Comparison Table
| Feature | TLS 1.2 | TLS 1.3 |
|---|---|---|
| Handshake round trips | 2-RTT | 1-RTT (0-RTT resumption) |
| Cipher suites | Many (including weak ones) | 5 strong AEAD-only suites |
| Forward secrecy | Optional (depends on cipher) | Mandatory (always on) |
| RSA key exchange | Supported | Removed (only ECDHE/DHE) |
| Browser support | Universal | All modern browsers |
| Released | 2008 | 2018 |
TLS 1.2: The Current Baseline
TLS 1.2 has been the standard since 2008 and remains widely supported. It introduced AEAD ciphers, SHA-256, and improved the handshake over earlier versions. However, TLS 1.2 still supports many legacy cipher suites including RSA key exchange, which does not provide forward secrecy.
The TLS 1.2 handshake requires two round trips between client and server before encrypted data can flow, adding latency to every new connection. Misconfigured servers may also negotiate weak ciphers if strong ones are not explicitly prioritized.
TLS 1.3: The Modern Standard
TLS 1.3 (RFC 8446, published 2018) is a significant overhaul. It reduces the handshake to a single round trip and supports 0-RTT resumption for returning clients. All weak cipher suites, including RSA key exchange, CBC mode, and RC4, were removed entirely.
Forward secrecy is mandatory in TLS 1.3 — every connection uses ephemeral key exchange (ECDHE or DHE). This means even if a server's private key is compromised, past sessions cannot be decrypted. The handshake itself is also encrypted, exposing less metadata to passive observers.
Deprecation of TLS 1.0 and 1.1
TLS 1.0 (1999) and TLS 1.1 (2006) were officially deprecated in RFC 8996 (March 2021). Both versions are vulnerable to known attacks including BEAST, POODLE, and CRIME. All major browsers dropped support in 2020. PCI DSS compliance requires TLS 1.2 or higher.
If your server still supports TLS 1.0 or 1.1, disable them immediately. Use our TLS Checker to verify which versions your server supports.
Which Version Should You Use?
The recommended configuration for most servers in 2026:
- Enable TLS 1.3 as the preferred protocol for best performance and security.
- Keep TLS 1.2 enabled as a fallback for older clients that do not yet support TLS 1.3.
- Disable TLS 1.0 and 1.1 — they are deprecated and insecure.
- Disable SSL 3.0 if it is somehow still enabled.
Check your server's cipher suite configuration with our Cipher Suite Checker.
Frequently Asked Questions
Should I disable TLS 1.2 and only use TLS 1.3?
Not yet for most servers. While TLS 1.3 is more secure and faster, some older clients only support TLS 1.2. Best practice is to support both TLS 1.2 and 1.3 while disabling TLS 1.0 and 1.1, which are deprecated and insecure.
How much faster is TLS 1.3 than TLS 1.2?
TLS 1.3 reduces the handshake from two round trips to one, cutting connection setup time roughly in half. With 0-RTT resumption, returning clients can send data immediately without any handshake round trips at all.
Are TLS 1.0 and 1.1 still safe to use?
No. TLS 1.0 and 1.1 were officially deprecated in RFC 8996 (March 2021). They use outdated cipher suites vulnerable to attacks like BEAST and POODLE. All major browsers have dropped support. You should disable them immediately.