Secure Shuffle

For a few months now, I have been using a secure disk image on my iPod Shuffle to transfer files between home and work. It's been working well enough, that I thought I'd share the procedure.

1. While I have an original 1 GB Shuffle, I only use about 512 MB for music. This is more than enough for mowing the lawn, driving or cycling to work. I configured the iPod to use the rest as data space.


2. I created a 100 MB encrypted disk image (Locker.dmg), and put it on the Shuffle.
   
3. Installed iPod Launcher on all of my Macs.
   
4. On my home Mac, I added an AppleScript that backs up the disk image to ~/Backup/YYYY-MMM-DD-TTT-Locker.dmg. I added this script to the iPod Launcher items. Admittedly, I didn't write all of this script, and I can't remember where I found it. (If you happen to know of the original, let me know and I'll give due credit.) I tweaked it quite a bit, so it will actually de-encrypt and compress the disk image.
   
5. On all of the Macs, I added Locker.dmg to the iPod Launcher items
   

So, I attach the Shuffle, the disk image auto-mounts, and I have access to my files. When I get home, the image is automatically backed up before its mounted (and yes, I backup ~/Backup, as well). Now, if my Shuffle is lost or stolen, I don't have to worry about personal or business data being compromised. For an added level of security, I only keep the password in the keychain of the backup Mac. I could be more secure and never store the password, but I'm more concerned about loosing the Shuffle than the iMac. And I change (and then forget) my password frequently enough that the backups would be worthless if they stayed encrypted.

I wouldn't mind finding a platform independent disk image format ... maybe PGP Disk?