Encrypt your data
Encrypt important data in Big Sur for better security and safer sharing
REQUIRES
macOS 11, external drive optional
YOU WILL LEARN
Different ways of encrypting things in Big Sur
IT WILL TAKE
10 minutes
JARGON BUSTER
A volume is a storage container for your data. You can split a physical disk or SSD into multiple volumes, each of which appears as a separate drive.
ENCRYPTION IS A great way to keep your personal data and files secure — it means that the only person who can access your data is you. In this tutorial, we’ll discover how to encrypt your Mac’s startup disk, external drives, and Time Machine backups — and we’ll also discover how to create disk images that you can share securely.
As far as your Mac is concerned a disk image is like any other disk, but as it’s a virtual drive you can have more than one on a single storage device. Disk images are ideal for emailing, for making available as downloads, or for uploading to shared cloud storage. But do make sure you don’t send the password with the image or you’ll defeat the whole purpose of encrypting your data.
There are four key options available to you here. A read/write disk image, aka a .dmg; a sparse image; a sparse bundle; and a CD/DVD master. With .dmgs you need to specify the file size, which is useful if you know that you’re dealing with a file size limit for uploads or email. Sparse images are more flexible; they can grow if more space is needed by the files they contain.
The difference is that a sparse image is one file and a sparse bundle is made of multiple files, so if you’re backing up and only a few things have changed, then a backup system such as Time Machine only needs to back up the changed bits of the bundle, not the whole thing. CARRIE MARSHALL