Create Encrypted Sparse Image for Private Client Data

This is a set of instructions for creating an encrypted "sparse bundle" disk image (even if you're not very technical). This is useful for keeping private data private. Even if you're computer gets compromised the data stored in these encrypted images won't be accessible without passwords. When you're done with the data it can be removed in one step (move/delete the sparseimage file).

Create New Image

Open Disk Image (press Cmd-Space, type Disk Image, press Return)

Select Custom Size

1. Give the file a name - this is the name of the .sparsebundle file that will be created
2. Give the image/volume a name - this is the name to be used when the image is mounted
3. Select "Custom..." from the size options

Set Custom Size

This will be a "sparse" image, so size doesn't matter here. The total disk space taken will grow with usage.

Select Encryption

If you're really paranoid, select 256-bit.

Select Sparse Bundle Image Format

Selecting "sparse bundle disk image" instead of "sparse disk image" is preferable. A sparse bundle is split into many 8MB chunks allowing Time Machine to only backup what has changed instead of copying the whole file to backup each time it is modified.

Create

Assign Password

If you want to be asked for the password each time you mount the image then uncheck "Remember password in my keychain".

Stored as .sparsebundle File

A .sparsebundle file should now exist in your home directory. You can 'mount' this image by double-clicking it.

Mounted in /Volumes

Whenever the image is mounted it will show up under the Devices in Finder. It may also appear on the desktop (depending on your preference settings). Note that it shows 130GB available even though the previous step showed it only taking 243MB. You can dismount the image by clicking on the eject icon.

This is where you're private data should be stored. I usually create a "Documents" directory here and link it back to my home Documents folder.

Turn On Spotlight Indexing

This is a bonus step to turn on Spotlight indexing for the new volume. If you make use of Spotlight (Cmd-Space) you will probably want to do this. Spotlight results will only contain entries from files in this volume if it is mounted.

• Open Terminal (Cmd-Space, type "Terminal", press Return)
• Change Directories to /Volumes/NAME (type "cd /Volumes/NAME", press Return) where NAME is the name of the image volume you created
• Run the mdutil command to enable indexing (type "mdutil -i on .", press Return)