https://arstechnica.com/information-technology/2018/02/new-tool-safely-checks-your-passwords-against-a-half-billion-pwned-passwords/

A new system that securely checks whether your passwords have been made public in known data breaches has been integrated into the widely used password manager, 1Password. This new tool lets customers find out if their passwords have been leaked without ever transmitting full credentials to a server.

Security researcher Troy Hunt this week announced his new version of "Pwned Passwords," a search tool and list of more than 500 million passwords that have been leaked in data breaches. Users can access it online and developers can connect applications to it via an API.