What You Need
– Mac OS 10.2 or later
What is an Encrypted Disk Image?
An encrypted disk image is a file that is 128-bit encrypted. When you double-click on this file, Mac OS X will prompt you for a password. Once authenticated, the disk image will mount on your Mac as if you had inserted a CD or USB flash drive. Once you have copied data to the mounted disk image, you can unmount the image and secure it. Anyone wanting to open your disk image will have to type your password to view its contents.
Here’s how to do it:
1. Launch the Disk Utility application. You can find this in Applications > Utilities.
2. From the File menu, select New Blank Image. Or, you can click the New Image icon on the toolbar.
3. Select the size you’d like the encrypted disk image to be. There are many options, but we recommend using the 610MB (CD-ROM 74 min) option. This will provide plenty of room, and the image will fit perfectly on a CD if you want to back up your data.
4. Make sure you select the AES-128 (recommended) option under the encryption menu. Name your image and click Create to save it.
5. Once you save your image, the Disk Utility application will prompt you for a password. Make sure you uncheck Remember password (add to Keychain). If you don’t uncheck this box, it defeats the purpose of the encrypted disk image. Anybody could walk up to your Mac and mount the image!
6. After the image is created, it will automatically mount for the first time. You can now copy files to the image. When you are finished, make sure you unmount the image by dragging its icon to the trash or selecting the eject button next to its icon in any finder window.
7. To mount the image again, simply double-click on the disk image you created. In the image below, our disk image is called personal.dmg. You’ll see it at the top of the list.
Remember to unmount your disk image when you are finished with it.
(alwi fata & indah herawati)