Clef provides easy-to-use strong two-factor authentication using smartphones.
https://wordpress.org/plugins/wpclef/
Widgets · WordPress Plugins
Get access to data on 284,996 websites that are Clef Two-Factor Authentication Customers. We know of 36,455 live websites using Clef Two-Factor Authentication and an additional 248,541 sites that used Clef Two-Factor Authentication historically and 19,282 websites in the United States.
Get a list of 284,996 websites using Clef Two-Factor Authentication which includes location information, hosting data, contact details, 36,455 currently live websites and an additional 4,286 domains that redirect to sites in this list. 248,541 sites that used this technology previously and 19,282 websites in the United States currently using Clef Two-Factor Authentication.