Today I discovered that in May, Microsoft quietly upgraded their free OneNote Web App to support password protected OneNote files.
Based on the highlighted section below, private-key AES encryption might have finally made its way to SkyDrive:
Of course, the bad news is that thanks to Snowden, we now know it’s likely that while Microsoft employees may not be able to view OneNote data without your password, the NSA probably can.
Still, this is better privacy than before, and it’s a nice option for OneNote access on a Mac. You’ll need to keep a full desktop version of OneNote around somewhere, because while you can access and modify password protected sections with the web app, you can only create them with the desktop version.
Another thing to keep in mind is that password protected sections are not yet able to be opened with OneNote for iOS:
Password support for OneNote on SkyDrive is a nice improvement, but it isn’t a functional replacement for the desktop version. Two years after my initial post on the same topic, there is still no OneNote equivalent that runs natively on OS X.
Here is Microsoft’s official Service Description of the Office Web Apps and a comparison with the desktop versions, but the information about password protected document support is out of date and incorrect, so there might be other inconsistencies as well. Updates to the Web Apps are evidently being released faster than updates to the online documentation.