> Lock your private data away
How do I best create a secure “vault” for important data so that it’s protected from others, including those with shared access to my Mac at work?
If you’ve got a lot of private files, it may be worth creating an encrypted APFS volume, but most prefer instead to use an encrypted disk image, which can either be a single DMG file or a sparse bundle.
DMG files are best if you want a fixed size which is easy to move around; they can be created in Disk Utility or DropDMG from bit.ly/ml183dropdmg. Sparse bundles consist of a whole folder, within which are “band” files. These allow a sparse bundle to grow by adding more bands. They too can be created using Disk Utility or DropDMG, and Spundle from bit.ly/ml183spundle. In High Sierra and later you can opt for either the traditional HFS+ format, or the latest APFS instead.
Double–click it to open the image and mount it in the Finder once you’ve entered its password. The only snag is that, once mounted, these are also accessible to other users, so you must be careful to ensure they’re ejected before you leave your Mac. You can also set the General tab of the Security & Privacy pane to require your Mac’s password immediately on sleep or the screensaver appearing.