Create custom basic auth. You can put it to access callback.
<?php
$user = variable_get('variable_user', 'user');
$pass = variable_get('variable_pass', 'pass');
if (!empty($_SERVER['PHP_AUTH_USER']) && isset($_SERVER['PHP_AUTH_PW'])
&& $_SERVER['PHP_AUTH_USER'] == $user
&& $_SERVER['PHP_AUTH_PW'] == $pass) {
return TRUE;
}
$print = variable_get('variable_print', 'Hello, user: [user], pass: [pass]!');
header(sprintf('WWW-Authenticate: Basic realm="%s"', strtr($print, array('[user]' => $user, '[pass]' => $pass))));
header('HTTP/1.0 401 Unauthorized');
exit;