• Skip to main content
  • Skip to primary sidebar
  • Home
  • About
    • Stephen Foskett
      • My Publications
        • Urban Forms in Suburbia: The Rise of the Edge City
      • Storage Magazine Columns
      • Whitepapers
      • Multimedia
      • Speaking Engagements
    • Services
    • Disclosures
  • Categories
    • Apple
    • Ask a Pack Rat
    • Computer History
    • Deals
    • Enterprise storage
    • Events
    • Personal
    • Photography
    • Terabyte home
    • Virtual Storage
  • Guides
    • The iPhone Exchange ActiveSync Guide
      • The iPhone Exchange ActiveSync Troubleshooting Guide
    • The iPad Exchange ActiveSync Guide
      • iPad Exchange ActiveSync Troubleshooting Guide
    • Toolbox
      • Power Over Ethernet Calculator
      • EMC Symmetrix WWN Calculator
      • EMC Symmetrix TimeFinder DOS Batch File
    • Linux Logical Volume Manager Walkthrough
  • Calendar

Stephen Foskett, Pack Rat

Understanding the accumulation of data

You are here: Home / Everything / Apple / Mac Users, Secure Your Stuff in Dropbox

Mac Users, Secure Your Stuff in Dropbox

July 5, 2011 By Stephen 8 Comments

Disk Utility in Mac OS X can create an encrypted "SparseBundle" compatible with Dropbox

Security is always possible but has rarely been easy. Storing unencrypted files and folders is much simpler and more compatible than going through the effort to use encryption. But the recent security flub at Dropbox set me looking for a secure way to store data there. Here’s a quick and easy way to create a secure, Dropbox-compatible disk image for Mac OS X.

Dropbox-Friendly

You might also want to read Keep Multiple Macs in Sync with Dropbox and Compression, Encryption, Deduplication, and Replication: Strange Bedfellows

Yesterday, “Storagemistress” suggested a method of securely hiding … “stuff” … using the excellent open-source software, TrueCrypt. This has the advantage of cross-platform compatibility and obfuscation (she suggests using a movie title as “cover”) but isn’t all that Dropbox friendly. Change one bit in that file, and the whole thing will have to be re-synced.

Mac users have a great alternative method: The SparseBundle. This has a few advantages over monolithic disk images:

  1. SparseBundles are thin provisioned, growing as data is added and only taking up as much space as is actually used (to the nearest 1 MB), while conventional disk images are entirely provisioned when they are created.
  2. SparseBundles store data in 1 MB “bands” that can be independently synchronized with rsync or Dropbox, as opposed to conventional images that are stored as a single file.

These two elements make SparseBundles excellent for securing valuable data while protecting it off-site. Dropbox loves the 1 MB bands, and I feel better knowing my data is encrypted in case the service has another “oops” moment.

Create Your SparseBundle

Creating a SparseBundle Disk Image is fairly straightforward. Note that this only works in Mac OS X 10.5 “Leopard” and newer releases.

  1. Launch Disk Utility – I like to just type that into Spotlight, but it’s in Applications/Utilities
  2. Click “New Image” as seen in the image at the top of this post
  3. Give your SparseBundle a file name in “Save As” and locate it in a folder (e.g., your Dropbox folder!)
  4. Disk Utility is all you need to create a secure storage location
  5. Enter a friendly name for the disk image – this can be the same or different from your file name
  6. We’ll leave “Format” and “Partitions” untouched
  7. Click the dropdown menu for “Size” and select “Custom” to enter a custom maximum file size
  8. Click “Encryption” to enable 128- or 256-bit encryption
  9. Click “Image Format” and select “sparse bundle disk image”
  10. Now click “Create” to start the image process
  11. Since we selected encryption, a new dialog box will appear asking for a password – this is what you will enter every time you use this image, and Apple helpfully rates your password strength for you
  12. Click “Ok” and you’re done – the bundle will mount as a new drive

As you add and remove files from this disk image, they will be encrypted and stored in 2 MB “slices” (actually files in a directory). These work great with Dropbox, Rsync, and many other utilities.

This image can be mounted on any Mac, provided the password is known. But don’t try to mount it on more than one machine simultaneously!

Note: If you want to obscure these files, you can rename the SparseBundle. It won’t be usable from Finder, but you can still mount it from the command line using hdiutil. But it’ll be a directory of equal-sized files, so you won’t fool anyone who knows what they’re doing.

Stephen’s Stance

Encryption is an important tool for individuals regardless of what they’re storing. Given the recent security failings of Dropbox, I highly recommend using methods like this to secure your important data before using the service!

You might also want to read these other posts...

  • Electric Car Over the Internet: My Experience Buying…
  • Liberate Wi-Fi Smart Bulbs and Switches with Tasmota!
  • What You See and What You Get When You Follow Me
  • Ranting and Raving About the 2018 iPad Pro
  • GPS Time Rollover Failures Keep Happening (But…

Filed Under: Apple, Everything, Personal, Terabyte home Tagged With: Disk Utility, Dropbox, encryption, Mac OS X, SparseBundle, Storagemistress, TrueCrypt

Primary Sidebar

The same thing can be identified by many different terms, and the same term may mean many different things.

Douglas John Foskett

Subscribe via Email

Subscribe via email and you will receive my latest blog posts in your inbox. No ads or spam, just the same great content you find on my site!
 New posts (daily)
 Where's Stephen? (weekly)

Download My Book


Download my free e-book:
Essential Enterprise Storage Concepts!

Recent Posts

Electric Car Over the Internet: My Experience Buying From Vroom

November 28, 2020

Powering Rabbits: The Mean Well LRS-350-12 Power Supply

October 18, 2020

Tortoise or Hare? Nvidia Jetson TK1

September 22, 2020

Running Rabbits: More About My Cloud NUCs

September 21, 2020

Introducing Rabbit: I Bought a Cloud!

September 10, 2020

Remove ROM To Use LSI SAS Cards in HPE Servers

August 23, 2020

Test Your Wi-Fi with iPerf for iOS

July 9, 2020

Liberate Wi-Fi Smart Bulbs and Switches with Tasmota!

May 29, 2020

What You See and What You Get When You Follow Me

May 28, 2019

GPS Time Rollover Failures Keep Happening (But They’re Almost Done)

April 6, 2019

Symbolic Links

    Featured Posts

    The Fat Middle: Today’s Enterprise Storage Array

    August 31, 2014

    What’s (Still) Wrong With Dropbox For Business

    April 17, 2013

    Scaling Storage In Conventional Arrays

    November 19, 2013

    Thoughts on the Modern Miracle of 3D Printing

    July 28, 2015

    The Prime Directive of Storage: Do Not Lose Data

    December 12, 2014

    What’s the Difference Between a Jailbroken and an Unlocked Phone?

    May 5, 2012

    How To Keep Your Family Activities In Sync With A Shared Google Calendar

    April 18, 2010

    Nimble Storage Rolls Out an All-Flash Array

    February 24, 2016

    Storage Changes in VMware vSphere 5.1

    September 4, 2012

    What is VMware VASA? Not Much (Yet)

    November 11, 2011

    Copyright © 2021 · Log in