Clef provides easy-to-use strong two-factor authentication using smartphones.
https://wordpress.org/plugins/wpclef/
Widgets · WordPress Plugins
Get access to data on 289,451 websites that are Clef Two-Factor Authentication Customers. We know of 35,456 live websites using Clef Two-Factor Authentication and an additional 253,995 sites that used Clef Two-Factor Authentication historically and 19,121 websites in the United States.
Get a list of 289,451 websites using Clef Two-Factor Authentication which includes location information, hosting data, contact details, 37,700 currently live websites which includes 2,244 domains that redirect to sites in the list. 253,995 sites that used this technology previously and 19,121 websites in the United States currently using Clef Two-Factor Authentication.