Website Trust

Secure websites (those starting with HTTPS) have a system where browsers rely on a limited number of trustworthy companies to manage this. This makes it relatively easy for users, but if any of these companies are compromised (which has happened!) or are willing to cooperate with a government that may be a threat to you, the entire trust network becomes a problem (this same model is also used for a specific type of email security which is called S/MIME).