tls_handshake
// Deep-dive into TLS 1.3 and 1.2 — every packet, every key, every state change
Step 0 / 0
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Client Random
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Server Random
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ECDHE Shared Secret
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Session Key (derived)
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What is TLS?
TLS (Transport Layer Security) is the cryptographic protocol behind the padlock in your browser. It wraps any TCP connection in a secure channel — providing confidentiality, integrity, and authentication. Click "step" to walk through every packet.
TLS 1.2 vs TLS 1.3 comparison
TLS 1.2 (2008)
Round trips2 RTT before data
Key exchangeRSA or DHE/ECDHE
RSA key exchangeNo forward secrecy
Server certSent unencrypted
Cipher suites37 suites, many weak
0-RTT resumptionNot supported
HMAC/PRFSHA-256/384
TLS 1.3 (2018, RFC 8446)
Round trips1 RTT before data
Key exchangeECDHE only (mandatory)
RSA key exchangeRemoved entirely
Server certEncrypted in flight
Cipher suites5 suites, all strong
0-RTT resumptionSupported (PSK)
HMAC/PRFHKDF (RFC 5869)