It’s a good thing we’re on friendly terms with New Zealand, because one of the residents of that green, hilly island recently acquired 60 pages of sensitive U.S. military data. Total cost of national secrets? $15. Which would’ve been great if that’s what the man who bought it was in the market for, but he was actually just looking for a working MP3 player, which Ars Technica reports the used iPod was not. Data found on the iPod included the personal information of military personnel, and details about mission briefings and deployment.

The purchaser of the used iPod, Chris Ogle, has been looking through the information, and even tried calling some of the numbers listed. Some of the calls actually connected with the correct individuals, indicating that the information is not, in fact, out of date. He also says he’s made the U.S. Department of Defense aware of the mix-up, but has yet to receive any word back from them. Maybe they’re hoping that if they stay real quiet this will all go away.

This is a fairly sensational example, but the fact is that many people don’t think about making sure their personal data is really gone from their iPod before selling it or trading it on the secondhand market through sites like eBay, Kijiji, and craigslist. Your iPod, just like a computer hard drive, contains data that can be recovered unless you go out of your way to make sure it can’t. Proper data erasure is even more important now that the iPod Touch can retrieve and store emails and other sensitive information.

If you have an older iPod that still supports disk mode, then you’ll want to use Disk Utility to completely reformat the drive, and then Restore the iPod using the latest firmware available for that model. Check out this useful tutorial describing exactly how to do that in detail for more info. You can also do a secure erase from Disk Utility, but for any of this to work you have to enable Disk mode on the device.

If you have an iPod touch, you could just do a Restore, which will wipe all your data, but to be extra safe, you may want to try formatting the iPod a couple different ways. First, go to Settings > General > Reset and choose the “Erase All Content and Settings” option. Once you’ve done that, proceed with a normal Restore when you connect the device to your computer, but set it up as a new iPod, instead of restoring from a backup.

That may still leave bits of information on your device, so here’s another method to try that involves writing over sensitive info with filler material and then erasing again, as described by Macsimum News:

1. Change passwords for all mail accounts that are synced to the iPhone or touch.
2. Make sure the device can no longer open the mail accounts.
3. Do an erase/restore of the iPhone or iPod touch, preferably using another computer or at least another account than the one the device was synced with.
4. Sync as many songs/videos of a non-compromising nature and nothing else to the newly restored device as will fit.
5. A good tool I recommend using to fill the drive up with data (songs/videos), is PhoneView. You can directly access the disk on your iPhone to totally fill it up.
6. After you have filled the drive up, do another erase/restore.
7. Repeat steps 4/5 with different content and erase/restore again. The more times you do this, the more times the data will be overwritten, thus having a less chance of recovery.

There you go, now you can make sure that if there’s a leak of sensitive information about your country’s military, it won’t have come from you.

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While I am a fan of the Terminal, sometimes remembering (or Googling for) the proper “defaults write ...” undocumented setting to tweak a feature on a new build or a friend’s machine gets a bit annoying (mostly due to my increasingly old age…Hey! You, kids! Get off my lawn!). If you ever wanted the opportunity to really muck things up across your system and installed applications, then head on over to the “Secret” BlackTree page (yes, the makers of the awesomeness that is QuickSilver) and grab a copy of their preference pane.

Truth be told, I actually needed to change out the text on the login window on my Mac (for work) and did not remember the /Library/Preferences/com.apple.loginwindow.plist file or key for it and just happened to come across the Secrets update today. I was impressed at the extent of its database of settings for all sorts of apps and the fact that it figured out which apps I had installed (so it only showed relevant settings options).

An example of the non-deadly, application-usefulness of Secrets comes from its Twitterrific preferences pane:

which provides access to some of the tweaks you can make that are published by the author but not available in the actual application preferences.

You can see feedback from others in the discussion group, tinker with the source code on your own and even submit your own l33t secrets to BlackTree.

If you know of any cool, hidden preferences or have feedback on Secrets that TAB readers should know, definitely drop a note in the comments.

Related research and analysis from GigaOM Pro:
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• Why iPad 2 Will Lead Consumers Into the Post-PC Era
• The Near-Term Evolution of Social Commerce
• Content Farms: The Players, The Benefits, The Risks