How Machines Trust Strangers Every secure connection rests on certificates — documents one party issues so another can verify a third. This site explains certificate chains, authorities and the padlock in your browser.

A signed document binding an identity — usually a domain name — to a cryptographic key. A party you already trust signs it, so you can trust a party you have never met.

Deliberately short lives limit the damage of stolen keys and force fresh verification of ownership. Automation makes the churn invisible when it is set up well.

That the connection is encrypted to the domain named in the address bar. It says nothing about whether that site is honest — trust in the operator is a separate question.