diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6d52aa7a..82fa47e3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Unreleased]
+
+### Fixed
+
+- Xlsx reader crashed when reading a file with workbook protection - [#553](https://github.com/PHPOffice/PhpSpreadsheet/pull/553)
+
 ## [1.3.1] - 2018-06-12
 
 ### Fixed
diff --git a/src/PhpSpreadsheet/Reader/Xlsx.php b/src/PhpSpreadsheet/Reader/Xlsx.php
index e9ac11bf..7a8f48b1 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx.php
@@ -2404,7 +2404,7 @@ class Xlsx extends BaseReader
         }
 
         if ($xmlWorkbook->workbookProtection['revisionsPassword']) {
-            $excel->getSecurity()->setRevisionPassword((string) $xmlWorkbook->workbookProtection['revisionsPassword'], true);
+            $excel->getSecurity()->setRevisionsPassword((string) $xmlWorkbook->workbookProtection['revisionsPassword'], true);
         }
 
         if ($xmlWorkbook->workbookProtection['workbookPassword']) {