A certificate is just a signed statement: 'I vouch that this public key belongs to this domain.' Understanding that single idea unlocks how HTTPS authentication actually works.
Public-key cryptography broke an ancient constraint: for the first time in history, two parties can communicate securely without ever meeting to exchange a secret first.
DV, OV, and EV certificates all provide identical encryption. The difference is how much identity verification theater you're paying for—and browsers have decided that theater doesn't help users.
Your browser trusts about 150 organizations to vouch for every website you visit. How Certificate Authorities became the gatekeepers of Internet trust—and what happens when they fail.
Every HTTPS connection depends on a cryptographic path from a website's certificate to a root your browser already trusts. Break any link in that chain, and the whole thing fails.
A CSR proves you possess a private key without revealing it—the cryptographic handshake that lets Certificate Authorities issue certificates to the right people.
A self-signed certificate is a reference letter you wrote about yourself—cryptographically valid but meaningless for proving identity to strangers. Learn when that's fine and when it's dangerous.
A wildcard certificate covers all subdomains with one private key—trading management simplicity for concentrated risk. Here's when that trade makes sense.
A SAN certificate is just a list of domains sharing one identity. That simplicity creates both power and peril.
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