Is WRM Safe for XML-based PowerPoint Files?
All the new Microsoft Office file formats that were introduced with Office 2007 are essentially XML-based. These new formats are distinctive with their X suffixes, so that PPT evolved as PPTX (similarly DOC as DOCX, and XLS as XLSX) -- these new file formats continue being used in all subsequent versions of Office on both Windows and Mac. However, they are all essentially ZIP files. The ZIP file acts as a wrapper that contain plenty of XML files and other media content.
So how far would any WRM (Windows Rights Management) protection help? Won't savvy users be able to unzip those files and get to the content, even without using any WRM credentials? We tested this scenario by adding a ZIP extension to a WRM protected PowerPoint PPTX file, and then tried to unzip the file.
However, the unzipped folder showed up as empty! Follow these steps to see how this process works:
- Make a copy of any WRM Restricted PowerPoint file, and save it to a folder that is easy to locate, such as your Desktop.
- Ensure that your system is set to show file extensions. Now, right-click the PowerPoint file, and choose Rename (or just press F2). Add a ".ZIP" without the quotes right after the name of the file - for example if your original file name was:
It would now be renamed to:
- Windows will warn you that renaming the file extension could render this file unusable -- but since you are just working on a test file for now, go ahead and ignore this error by clicking the Yes button that you can see in Figure 1.
Figure 1: Change the file extension?
- Now that you have changed the PPTX to a ZIP file, go ahead and try to unzip the ZIP. We just right-clicked the ZIP file, and chose the Extract option in the resultant contextual menu.
- Surprise! This brings up a message window that indicates that the compressed (zipped) folder is empty, as shown in Figure 2.
Figure 2: An empty Zip file!
- Even double clicking the ZIP will bring up an error message, as shown in Figure 3.
Figure 3: Just a ZIP, no unZIP!
This indicates that your WRM (Windows Rights Management) protected presentation is actually fully protected!
July 2004 | August 2004 | September 2004 | May 2005 | June 2005 | July 2005 | November 2005 | February 2006 | April 2006 | June 2006 | September 2006 | October 2006 | December 2006 | February 2007 | May 2007 | August 2007 | November 2007 | February 2008 | October 2008 | June 2009 | November 2009 | January 2010 | August 2010 | October 2010 | November 2010 | December 2010 | February 2012 | August 2012 | October 2012 | July 2014 |
Microsoft and the Office logo are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries.