Index: src/wp-includes/post-template.php
===================================================================
--- src/wp-includes/post-template.php	(revision 34110)
+++ src/wp-includes/post-template.php	(working copy)
@@ -450,6 +450,19 @@
 			$classes[] = 'format-standard';
 	}
 
+	// Post is protected
+	if ( ! empty( $post->post_password ) ) {
+		$classes[] = 'visibility-protected';
+	}
+
+	if ( 'private' === $post->post_status ) {
+		$classes[] = 'visibility-private';
+	}
+
+	if ( 'public' === $post->post_status ) {
+		$classes[] = 'visibility-public';
+	}
+
 	// Post requires password
 	if ( post_password_required( $post->ID ) ) {
 		$classes[] = 'post-password-required';