Basic Auth for Wordpress.

HTTP Authentication lets you make a site without letting anyone view it without valid credentials. This can protect the full site or only admin pages.

Lockdown WP Admin conceals the administration and login screen from intruders. It can hide WordPress Admin (/wp-admin/) and and login (/wp-login.php) as well as add HTTP authentication to the login system. We can also change the login URL from wp-login.php to whatever you'd like: /login, /log-in-here, etc.