Manual:$wgSecureLogin/ja

詳細
If true, forces users to authenticate using https when they come from http, but only if you use a protocol-relative URL in  (otherwise this setting is ignored). Note also that under certain circumstances, when serving http and https in parallel on a web server, specifying http within a browser's location and adding the  query parameter, the login page will be downgraded from https to http, even when   is set to true. A link will then display above the username field allowing a user to choose the secure login option.

From 1.22 on, use  to set   false by default if you want HTTP users to stay on HTTP after login by default.

wikitech-l での George Herbert のアイデアに基づいています: wikitech-l/2010-October/050071.html

$wgServer に以下のように設定する必要があります.