--- wp-includes/post-template.php.orig	2012-09-07 09:14:42.000000000 +0100
+++ wp-includes/post-template.php	2012-09-15 18:15:36.000000000 +0100
@@ -336,6 +336,8 @@
 	}
 
 	// post requires password
+	if ( !empty($post->post_password) )
+		$classes[] = 'protected';
 	if ( post_password_required($post->ID) )
 		$classes[] = 'post-password-required';