Clave a dominio

https://www.dondominio.com/help/es/184/proteger-directorios-con-contrasena-mediante-htaccess/

https://www.digitalocean.com/community/tutorials/how-to-set-up-password-authentication-with-apache-on-ubuntu-14-04

htaccess

AuthName 'Restricted Area'
AuthType Basic
require valid-user
AuthUserFile /var/www/.htpasswd