Clef provides easy-to-use strong two-factor authentication using smartphones.
https://wordpress.org/plugins/wpclef/
Widgets · WordPress Plugins
Get access to data on 261,714 websites that are Clef Two-Factor Authentication Customers. We know of 25,193 live websites using Clef Two-Factor Authentication and an additional 236,521 sites that used Clef Two-Factor Authentication historically and 13,391 websites in the United States.
Get a list of 261,714 websites using Clef Two-Factor Authentication which includes location information, hosting data, contact details, 25,193 currently live websites and an additional 3,140 domains that redirect to sites in this list. 236,521 sites that used this technology previously and 13,391 websites in the United States currently using Clef Two-Factor Authentication.