Encrypting just a few files
QI don’t want to use FileVault to secure my entire disk, but have a couple of folders with sensitive files that I want to lock and protect. What’s the best way to achieve this?
AIf you’re running High Sierra or later and the disk is formatted in Apple’s new file system, APFS, it’s simple to create an encrypted APFS volume on that disk without losing space or running the risk of erasing the whole disk. APFS allows multiple volumes on each disk (‘container’) without allocating them separate space.
In Disk Utility, select the Container disk1 and choose Edit > Add APFS Volume. When the app prompts you to choose the format for that volume, choose APFS (Encrypted), then enter a strong password. When your new encrypted volume is ready for use, copy your sensitive files to it and trash the originals. You can then eject that volume alone. When you want to access those files, you’ll be prompted for the password to mount your encrypted volume and its contents.
If you’re still using Apple’s older Mac OS Extended file system, or don’t want to alter the partitioning of your drive, make an encrypted disk image using Disk Utility instead, move the files into it, and open the image when you want to access the files.
Choose File > Blank Image, and set the Encryption pop-up menu to either 128- or 256-bit AES. Set Image Format to ‘sparse bundle disk image’, which allows the image to occupy only the space needed – up to the maximum you choose in the Size pop-up.