Security Architecture 6 min read Published January 31, 2025

TLS 1.3 vs TLS 1.2: Handshake Speed, 0-RTT, Ciphers, and Performance Benchmark

Technical benchmark comparing TLS 1.3 and TLS 1.2 latency, round trips (1-RTT vs 0-RTT), and cipher security.

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CheckSSLExpiry Security Research Team SSL/TLS Security & Cryptographic Reliability

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1. Handshake Round-Trip Comparison

TLS 1.2 Handshake: Requires 2 full round-trips (2-RTT) of back-and-forth communication before encrypted application data can be sent.
TLS 1.3 Handshake: Reduces negotiation to 1 round-trip (1-RTT) for new connections and 0-RTT for returning visitors. This shaves 50–100ms off initial page load times.

2. Elimination of Insecure Legacy Cryptography

TLS 1.3 removed all vulnerable cryptographic primitives:

✕ Removed RSA key exchange (ensuring Forward Secrecy is mandatory via (EC)DHE).
✕ Removed CBC-mode ciphers (eliminating Lucky13 and BEAST vulnerabilities).
✕ Removed RC4, 3DES, MD5, and SHA-1.

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