Selling iphone: Secure erase data?

lumine01

macrumors member
Original poster
Feb 23, 2008
30
0
Is data recovery something that can be done on an iPhone, after it has been "wiped" and reset to factory defaults?

Is there a way to "secure erase" any of the old files, other than overwriting the old data with newer files?

Thanks for any advice/help!
 

cruisin

macrumors 6502a
Apr 1, 2014
962
223
Canada
I would first erase all settings since this is what will wipe everything. A restore should delete the encryption key but won't do anything for an older phone. This apple link explains it best. Older devices overwrite everything and newer devices delete the encryption key. Either way, you should be fine. Since this is part of the OS, it should work much better than any app you can get.

If you are paranoid, you can erase then restore as a new phone and then erase again.

A bigger worry is the weird way text messages are handled if you switch to a non-Apple phone and don't sign out of iMessage. You might not get your texts. See: Deregister iMessage.
 
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lumine01

macrumors member
Original poster
Feb 23, 2008
30
0
That helps a lot, thanks for taking the time to explain it!
 

rigormortis

macrumors 68000
Jun 11, 2009
1,813
229
the iPhone uses 256 bit encryption. every iPhone since the a4 system on a chip has had this feature.

the iPhone is secure as long as you don't write the key down.

when people say "30 characters should be enough !" on your wifi network, that is what your iPhone is dong automatically.

dvd uses 40 bit keys and blu ray uses 128 bit keys. they would of had a hard time ripping star wars and terminator , if the keys weren't discovered, and given away

don't write it down means don't jail break your device. if you jailbreak your device , it might backup your key somewhere.

if you had a computer and it made 1 trillion guesses per second to try and get back the data you wiped, it would take :

3.53 hundred million centuries

here is a good reddit post
http://www.reddit.com/r/theydidthem...e_and_energy_required_to_bruteforce_a_aes256/

a lot of crypto people say that AES-256 is so secure, that even the quantum computers in the future can't brute force your iPhone. (meaning the iPhone can't be recovered in the average human beings lifetime or the lifetime of the known universe)

they can go after itunes backups and iCloud. but the iPhone, i doubt it
 
Last edited:

Andy2k

macrumors member
Jul 18, 2015
68
13
If you're really paranoid. You can do a full restore and download iOS from itunes. That will reload the entire operating system which should completely write over your data. Press and hold both the power button and home button down until it boots into "recovery mode" Then plug it into your computer and launch iTunes. iTunes will detect it in recovery mode and ask if you'd like to download the newest iOS and restore your phone. Essentially doing a full factory reset on the phone.

Is data recovery something that can be done on an iPhone, after it has been "wiped" and reset to factory defaults?

Is there a way to "secure erase" any of the old files, other than overwriting the old data with newer files?

Thanks for any advice/help!
 

Eldiablojoe

macrumors 6502a
Dec 4, 2009
943
68
West Koast
Okay, so if I go to Settings, General, Reset, and then erase all data, does that restore the phone as new so I can sell it to someone else?
 

Gav2k

macrumors G3
Jul 24, 2009
9,217
1,606
Okay, so if I go to Settings, General, Reset, and then erase all data, does that restore the phone as new so I can sell it to someone else?
If you turn find my iPhone off and sign out of iCloud first.
 

Tech198

macrumors G5
Mar 21, 2011
14,649
1,842
Australia, Perth
Is data recovery something that can be done on an iPhone, after it has been "wiped" and reset to factory defaults?

Is there a way to "secure erase" any of the old files, other than overwriting the old data with newer files?

Thanks for any advice/help!
When 'erase all content and settings', Apple only overwrites the secure keys, not the data itself, But since the data is encrypted anyway, no one can access anything they could recover, since the keys are gone.

if recovery software was possible, it wouldn't work. as it wouldn't see any data that anyone could use.

I got the same 'itch' till i released its impossible to tell without the keys.
 

Mac03ForLife

macrumors regular
Sep 19, 2017
154
25
Washington, DC
Try completely erasing the phone (so theres no iOS on it anymore), you should be able to use Disk Util for this.
Then, go and find an iPSW file that you can use (IPSWs are similar to boot media) then, sideload the ipsw into your phone (again using disk utility, through the restore function).

See if this works, let me know if it works, as this is a highly educated theory.:)
 

cruisin

macrumors 6502a
Apr 1, 2014
962
223
Canada
Try completely erasing the phone (so theres no iOS on it anymore), you should be able to use Disk Util for this.
Then, go and find an iPSW file that you can use (IPSWs are similar to boot media) then, sideload the ipsw into your phone (again using disk utility, through the restore function).

See if this works, let me know if it works, as this is a highly educated theory.:)
iOS does not expose the raw filesystem, so a iOS device will not show up in Disk Utility. A quick check shows that an iPhone will not show up. Perhaps you were thinking of a pre-iOS iPod?
 

Mac03ForLife

macrumors regular
Sep 19, 2017
154
25
Washington, DC
iOS does not expose the raw filesystem, so a iOS device will not show up in Disk Utility. A quick check shows that an iPhone will not show up. Perhaps you were thinking of a pre-iOS iPod?
Oh okay... I think I was, I also read somewhere that you can restore iOS 8 using one of the IPSW files.
Ill have to look more into it
 

cruisin

macrumors 6502a
Apr 1, 2014
962
223
Canada
Oh okay... I think I was, I also read somewhere that you can restore iOS 8 using one of the IPSW files.
Ill have to look more into it
You can use a IPSW file to restore, but you can only use the most recent version for the device and you have to go through iTunes. There is some wiggle room of about a week when a new version is released where you can use the previously released version, but in general you must use the most recent. You might as well just open iTunes and press restore.

The version is checked against Apple's servers, so it is very difficult to use an IPSW other than the preselected one.
 

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