Securely Erasing iPhone

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Securely Erasing iPhone

Apple has determined that the only solution to the problem with my iPhone is to replace the phone.

The Geniuses have assured me that if I "Restore" the iPhone, but (rather than let it complete the Restore process) unplug it from the computer once it shows the "Verifying and Restoring" message (this is the point, I am told, after the phone's memory has been wiped, but before the Mac has put a fresh OS back into the phone's memory), the iPhone's memory will be completely empty and its prior contents will not be accessible. (In this state, the iPhone cannot be used until it has been reattached to the computer and the computer has Restored an OS onto it.)

I'm interested in making sure my contact names and addresses are truly erased forever. I cannot find anything on the Internet that indicates how to securely erase the iPhone memory. All of the memory erase software requires that the target memory card or device show up as a disk in the Finder, which, of course, the iPhone does not.

Some information that I read indicates that flash memory, even when erased, still leaves traces of the data behind. Other information that I read indicates that flash memory does not leave traces that be converted into meaningful data. I don't know which to believe.

So...

1. Is there a need to do anything more than what the Geniuses suggest?

2. If so, what can I do to make the data is no longer accessible?

Any help is appreciated.

RDFrelay

MacBook Pro 15.4 2.0 GHz, Mac OS X (10.5.2), iPhone

Posted on May 16, 2008 1:44 PM

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Answer 1

May 16, 2008 2:51 PM in response to RDFrelay

Are you planning on selling or giving this iPhone to someone else?

Go to Settings > General > Reset and select Erase All Content and Settings.

This should be all that is required. You can follow this by restoring your iPhone as a new iPhone, or not from your iPhone's backup. This will completely erase your iPhone - again, and then install the current firmware version. Don't follow this by a sync.

All of the memory erase software requires that the target memory card or device show up as a disk in the Finder, which, of course, the iPhone does not.

The iPhone does not support what is called disk mode which is required for this. Since you can't mount your iPhone as an external drive in order to use a drive utility to erase it (I don't believe there are any which are iPhone compatible anyway), it will be difficult for someone else to do the same in order to extract this data.

Apple will be including a remote wipe feature for Exchange admins with firmware update 2.0. The remote wipe will likely do the very same as selecting Erase All Content and Settings via the Reset option - but the it may take it a little further by erasing the firmware and all software.

If you follow what I provided, this will amount to erasing your iPhone twice.

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Answer 2

RDFrelay Author

Level 1

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May 16, 2008 5:54 PM in response to Allan Sampson

Allan:

Thank you very much for your reply. I am not planning on selling it or giving it away-- Apple will be taking it and giving me a replacement.

Some of the reason I'm concerned that the "Erase all content..." option and the "Restore" options do not totally erase the memory is because of the recent posts at these links:

http://arstechnica.com/journals/apple.ars/2008/05/05/paranoid-about-privacy-care ful-restoring-your-iphone-then

http://www.zdziarski.com/

These seem to indicate that the options Apple provides do not really erase the data.

Do you have any idea if my concerns are well founded, based on these articles?

Thanks...

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Answer 3

Mac-Medic

Level 6

17,301 points

May 16, 2008 6:52 PM in response to RDFrelay

Why don't you just use something like iPhoneDrive and fill the drive completely up with a bunch of photos or something. It should overwrite any data on there now. You could do another restore too and repeat the process.

I wouldn't be to worried though. Depending upon the problem with yours, the logic board with the NAND flash drive may be trashed and replaced with a new one when they refurbish it.

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Dave M.
MacOSG Founder/Ambassador  An Apple User Group 
Creator of Mac611 - Mobile Mac Support (designed exclusively for an iPhone/iPod touch)

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Answer 4

RDFrelay Author

Level 1

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May 17, 2008 4:30 AM in response to Mac-Medic

Thank you for your reply, Dave.

I have a limited understanding of how flash memory (here, NAND, I'm told) works. Are you saying that any data recovery techniques would only be able to "see" the data that was last written to the flash memory before the most recent "Restore", and not data from previous writes (for example, over the months I've had the phone)?

Meaning, if I simply return the iPhone to a factory state (without any of my contacts or anything else), and then fill it completely with songs (essentially writing over all of the available memory), and then Restore it again to a factory state (with no data), that no data other than those songs would be accessible?

I guess I'm just trying to figure out, if what those links say are true, how one would prevent data from being accessible by people who try to steal data.

Thanks again for your help.

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Answer 5

May 17, 2008 6:32 AM in response to RDFrelay

Regarding deleted data on any type of drive - once the area on the drive where the data was stored has been overwritten by other data, it is impossible to recover the previously deleted data by any means.

The only people that will have a chance or access at acquiring any data will be the AppleCare personnel. If your iPhone is exchanged, it will not be sent out as a refurbished iPhone with any of your data available on it.

Even if so, what will it possible include that someone with a compatible data recovery utility can gain - some email account information, and some contact information?

It is one thing to be aware, concerned, and careful, but I wouldn't be so overly concerned over your email account information, and contact information. You can change the password for your email accounts, and contact information can be easily discovered on the internet. Other than that and don't take this personal, but I seriously doubt anyone that develops a data recovery utility, and goes to any trouble will be interested in this so they can read your email.

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Answer 6

May 17, 2008 10:48 AM in response to RDFrelay

I'm pretty confident that the extra measures suggested in the ars technica article will do a good job of wiping the phone.

Matt

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Answer 7

RDFrelay Author

Level 1

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May 17, 2008 1:00 PM in response to Allan Sampson

Thank you again, Allan, and thank you, Matt.

True, my email and contact information is not particularly interesting or valuable. I do suspect that the Ars Technica article information would sufficiently erase everything. I'm not certain, though.

My understanding is that writing over the data once will not prevent the overwritten data from being obtained. My understanding of hard drive secure erasing is that it involves copying random data multiple times over the confidential data-- that writing once is not enough-- that the confidential information can be obtained by some measuring of the magnetic strength of each bit (or something like that).

I'm told that flash memory behaves differently, but I can't seem to find information that clarifies what it takes to securely erase flash memory. I'm not certain that writing once will do the trick, or even that multiple times will do the trick. Ars Technica suggests overwriting the entire phone memory a few times, but of course not with random data, because you can't get access directly to the phone memory as a drive.

The other article suggests that Apple did indeed send out a refurbished phone with old information still on the flash memory. That surprises me, but would not be out of the realm of possibility.

Any insight about all this is appreciated.

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