How HTTPS Works

Watch the full TLS handshake animated step by step — Client Hello, certificates, key exchange.

Click "Start Handshake" to see the full TLS/HTTPS handshake animated.

What this HTTPS visualization shows

Watch the TLS handshake animate step by step — Client Hello, the server's certificate, key exchange, and the switch to an encrypted session. It makes the half-second of negotiation behind every padlock icon visible and understandable.

How HTTPS works

HTTPS is HTTP running inside TLS. The handshake does three jobs: authenticate the server (its certificate is signed by a Certificate Authority your browser trusts), agree on keys without ever sending them in the clear (modern TLS uses an ephemeral Diffie-Hellman exchange), and then switch to fast symmetric encryption for the actual data. The result: eavesdroppers see only ciphertext, and you know you're talking to the real server, not an impostor.

Why it matters

HTTPS is what makes logins, payments, and private browsing safe, and it's now a ranking and trust signal too. Understanding the handshake helps you debug certificate errors and mixed-content warnings. See what happens before the connection in how DNS works.

Frequently asked questions

What's the difference between SSL and TLS?

TLS is the modern successor to SSL. "SSL" is still used colloquially, but every secure site today actually uses TLS (1.2 or 1.3).

What does the padlock icon actually mean?

That the connection is encrypted and the server presented a valid certificate. It does not guarantee the site itself is trustworthy — only that the channel is private.

What is a Certificate Authority?

A trusted third party that signs certificates. Your browser ships with a list of CAs it trusts, which is how it verifies a server's identity.