How to Secure Microsoft Office Files

Man on the phone at his office
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Depending on the version of Microsoft Office you are using, it may contain a variety of applications. The base offering typically contains Word, Excel, PowerPoint and Outlook. PowerPoint does not seem to offer any inherent security, but Word, Excel, and Outlook all provide some level of encryption.

Securing Word Docs

For Microsoft Word documents (Word 2000 and newer), you can choose a higher level of security when saving a file. Rather than simply clicking "Save", click File, then Save As and follow these steps:

  1. Click on Tools in the upper right corner of the file save dialog box
  2. Click on Security Options
  3. The Security Options box provides a variety of options:
    • You can enter a password in the box next to Password to open if you wish the file to be completely inaccessible without the password
    • In Word 2002 and 2003, you can click on the Advanced button next to the password box to choose a higher level of encryption that is even harder to break into
    • You can enter a password in the box next to Password to modify if it is OK for others to open the file, but you want to restrict who can make changes to the file
  4. The bottom of the Security Options box also provides some choices to protect the privacy of the document:
    • Remove personal information from file properties on save
    • Warn before printing, saving or sending a file that contains tracked changes or comments
    • Store random number to improve merge accuracy
    • Make hidden markup visible when opening or saving
  5. Click OK to close the Security Options box
  6. Select a name for your file and click Save

    Securing Excel Files

    Excel offers a very similar style of protection to Microsoft Word. Just click on File, Save As and follow these steps:

    1. Click on Tools in the upper right corner of the file save dialog box
    2. Click on General Options
    3. You can enter a password in the box next to Password to open if you wish the file to be completely inaccessible without the password​
      • You can click on the Advanced button next to the password box to choose a higher level of encryption that is even harder to break into
    4. You can enter a password in the box next to Password to modify if it is OK for others to open the file, but you want to restrict who can make changes to the file
    5. Click OK to close the General Options box
    6. Select a name for your file and click Save

    Securing Outlook PST Files

    The actual digital signing and encryption of incoming or outgoing email messages and their file attachments is a whole separate issue which will be explained another time. However, if you happen to export data from your Microsoft Outlook folders into a PST file, you can add protection to ensure the data is not accessible by others. Just follow these steps:

    1. Click on File
    2. Select Import and Export
    3. Choose Export to a file and click Next
    4. Select Personal folder file (.pst) and click Next
    5. Choose the folder or folders you wish to export (and select the box to Include subfolders if you wish) and then click Next
    6. Pick an output path and file name and select one of the options for your export file, then click Finish
      • Replace duplicates with items exported
      • Allow duplicate items to be created
      • Do not export duplicate items
    7. Under Encryption Setting, choose one of the following options
      • No encryption
      • Compressible encryption
      • High encryption
    8. At the bottom of the screen, enter a password to use to open the encrypted PST file (you must enter the same password in both boxes to verify that you spelled the password the way you intended, otherwise you might not be able to open your own file)
      • Select whether or not to also Save this password in your password list
    9. Click OK to complete the file export

    (Edited by Andy O'Donnell)