Microsoft Excel file encryption allows you to quickly and easily secure PowerPoint presentations. Though early versions of Office’s file encryption were notoriously weak, newer versions are much stronger. Microsoft Office 2007-2010 offers AES-128 encryption using the SHA-1 algorithm, while Office 2013 uses AES-128 and SHA-512. The use of SHA-512 is a major upgrade over SHA-1 in preventing brute-force attacks against passwords.
Unlike the Office Suite for Windows, the Mac versions of Excel, PowerPoint, and Word have slightly different interfaces. Encrypting an Excel spreadsheet on Mac is different enough from encrypting a Word document that I chose to cover the two separately.
Microsoft PowerPoint File Encryption
To encrypt a spreadsheet, open Microsoft Excel. Click on the File menu, and from the drop-down select “Passwords”.
A new dialogue will appear. If you wish to encrypt the document, enter a password beside “Password to open”. Unlike Microsoft Word for Mac, I have found no meaningful limit on password length with Microsoft Excel file encryption. I have successfully used passwords as long as 60 characters. When you have entered your password, click “OK”. A password confirmation prompt will appear. Enter your password again and click “OK”.
The “Password to modify” prevents the presentation from being modified without the correct password. I have found this password limit to be inconsistent with the rest of the suite and capped at 15 characters.
Microsoft Excel file encryption is an excellent, user-friendly tool for protecting sensitive files. If you have extremely sensitive presentations you may wish to further protect them behind full disk encryption or volume level encryption.
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