Extension: Advanced Security
Description
Registration Form Security extension allows you to add extra security options to your registration forms including banning IPs, Spammy Domains, reserve important usernames and define password strength options.
WordPress Registration Plugin
RegistrationMagic Gold
Notes
Registration Form Security extension is part of RegistrationMagic Gold. Note that RegistrationMagic extensions are part of bundles; extensions are not available (or sold) individually.
Link
This extension is available here.