TOPIC NETWORKING
TLS how encryption happens before the lock icon appears
IN 10 SECONDS
A handshake where the client and server agree on a cipher, exchange keys, and verify identity via a certificate chain. After that, every byte is encrypted with a session key only they know.
GOTCHA Certificate expiration is the #1 TLS failure. It doesn't matter if the chain is perfect — an expired cert breaks everything.
HOW A TLS HANDSHAKE FLOWS
01 Client sends a `ClientHello` listing supported cipher suites and TLS versions.
02 Server responds with its chosen cipher, a session ID, and its certificate chain.
03 Client validates the certificate against trusted CAs, then generates a `pre-master secret` encrypted with the server's public key.
04 Both derive the same session keys from the pre-master secret and switch to encrypted communication.
POKE IT YOURSELF
openssl s_client -connect supraj.dev:443 -showcerts — inspect the full certificate chain
curl -vI https://supraj.dev — watch every TLS handshake step
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