Concept ASP.NET Core MVC 2 site for implementing password check based on data of Haveibeenpwned.com v2 API. HIBP API is based on data of password breaches of +/- 500 million passwords.
"Have I been pwned?" is the source of the data. See more info at https://haveibeenpwned.com/API/v2 HIBP API is rate-limitted at 2500ms (prefered 2600ms), so take this in consideration.
Register password user notifcation, when entering unsafe password (for example "P@ssw0rd").
Explanation page about data breaches and using a password manager.