A password strength checker is a web tool that instantly evaluates how secure
a user password is by analyzing its syntax and flagging potential
weaknesses. The tool checks if certain sequences of characters are being used, such
as proximity keys “asdf" and "qazwsx", or very common weak passwords like "123456"
and "password1". Other key factors assessed are the combination of alphanumeric
characters and symbols used, the number of characters, and password uniqueness.