Paid Memberships Pro Strong Passwords Addon GPL Overview:
Require members to use “Strong” passwords based on required characters.
This Add On checks to make sure the user has submitted a strong password by checking for length, lowercase/uppercase, numbers, special characters, and matching username.
The WordPress Password Strength Meter Calculator is also included, allowing members to see how strong their password is. Developers can alter the password requirements by commenting out certain checks as well as adjust or remove the “hint” added to the password field on the checkout page.