How To Encrypt a Folder On MacOS Using Disk Utility.
On Windows, you have Bitlocker. Cross platform, you also have VeraCrypt (successor to TrueCrypt). But if you want to encrypt a folder on the fly in MacOS, then the fastest and easiest way is to use Disk Utility.
Disk Utility is a feature built into the macOS operating system that can perform actions such as cleaning and formatting macOS hard drives and removable media such as USB drives. But it can also take a folder on macOS and encrypt it with DMG format.
If the DMG format sounds familiar to you, then this is probably because it is also the standard file format for macOS software installation files. DMG files are mountable disk images that compress the files inside them, much like a Zip file compresses Windows files in a folder.
DMG can not only compress files but also encrypt them. Here’s how.
Create an encrypted folder in Disk Utility
Create Encrypted Folder in Disk Utility
Create a new folder on your computer and put all the files you want to encrypt into it.
Now open Disk Utility, which you will find by selecting Applications– Utilities.
Go to the menu at the top and select File New Image Image from Folder.
Now navigate to the secret files folder, which in my case is on the desktop. Highlight a folder and click Select.
In the pop-up window, confirm the following:
- File name for the encrypted folder.
- Where do you want to save it.
- Encryption standard (usually 128-bit is sufficient).
- Set “Aspect Ratio” to “Read / Write”.
When you set the encryption standard, a password window will appear asking you to enter the desired password.
If you already have the desired password, enter it twice and click Select. However, if you are unsure of your password, the little black key icon next to the Confirm field means Password Assistant. Click the key to open it.
Expand the menu and choose what type of password you want. When you do this, the password will be automatically filled in in the fields provided.
You can also specify how long the password will be and the quality bar will update in real time.
It’s worth noting that if you choose the random password option, you’ll need to copy and paste it somewhere to remember. Or better yet, use a password manager. The last thing you need is to lock your own encrypted folder.
When you have the password you want, close the Password Assistant and you will be returned to this window.
Click “Save” to start the encryption process. How long it takes depends on the size of the encrypted folder.
When the DMG file is created, the original unencrypted folder will still be there. It is not removed by Disk Utility. So you can delete this folder, but as I just said, first make sure you have a copy of the password. Otherwise, you will be permanently blocked.
If you go to the newly created encrypted DMG file and double click on it, it will ask you for a password. DO NOT check the Keychain Access box.