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RFC 2818 - Quick Reference

Quick Reference​

HTTPS vs HTTP​

FeatureHTTPHTTPS
Protocolhttp://https://
Port80443
Encryption❌ Cleartext✅ TLS encrypted
Integrity❌ No protection✅ MAC protection
Authentication❌ No server auth✅ Certificate auth
Privacy❌ Can be eavesdropped✅ Encrypted transmission

TLS Handshake Overview​

Client                           Server
  |                                |
  |--- ClientHello --------------->|
  |                                |
  |<-- ServerHello, Certificate ---|
  |<-- ServerHelloDone ------------|
  |                                |
  |--- ClientKeyExchange --------->|
  |--- ChangeCipherSpec ---------->|
  |--- Finished ------------------>|
  |                                |
  |<-- ChangeCipherSpec -----------|
  |<-- Finished -------------------|
  |                                |
  |=== Encrypted Channel =========|
  |                                |
  |--- Encrypted HTTP Request ---->|
  |<-- Encrypted HTTP Response ----|

Common Tools​

# OpenSSL view certificate
openssl s_client -connect www.example.com:443 -showcerts

# Test TLS version
openssl s_client -connect www.example.com:443 -tls1_2

# View certificate details
echo | openssl s_client -connect www.example.com:443 2>/dev/null | \
  openssl x509 -noout -text

# cURL use HTTPS
curl -v https://www.example.com