A shut padlock indicating an encrypted or protected connection.
A closed padlock in a browser's address bar means the connection is encrypted. It has never meant the site is trustworthy, and treating it as a safety badge is a documented and consequential misreading.
In a browser address bar, indicates that traffic to the site is encrypted in transit.
Contexts: Software
Does not indicate that the site is honest or safe. Certificates are freely available, so a fraudulent site can display the same padlock as any other — a misreading serious enough that browsers have de-emphasised the icon in response.
Contexts: Software
Outside the browser, marks a locked or protected item generally.
Contexts: Software
A rounded arch rising from the top corners of a squared body beneath it, the arch closed at both ends where it meets the body.
Both are built from objects, and both are used in software contexts.