Clef provides easy-to-use strong two-factor authentication using smartphones.
https://wordpress.org/plugins/wpclef/
Widgets · WordPress Plugins
Get access to data on 261,566 websites that are Clef Two-Factor Authentication Customers. We know of 26,252 live websites using Clef Two-Factor Authentication and an additional 235,314 sites that used Clef Two-Factor Authentication historically and 14,057 websites in the United States.
Get a list of 261,566 websites using Clef Two-Factor Authentication which includes location information, hosting data, contact details, 26,252 currently live websites and an additional 3,429 domains that redirect to sites in this list. 235,314 sites that used this technology previously and 14,057 websites in the United States currently using Clef Two-Factor Authentication.