iPad restoring iPad as new is really effective in deleting data?

Discussion in 'iPad' started by ipaddaro, Dec 29, 2014.

  1. ipaddaro macrumors regular

    Dec 6, 2014
    I think i'll go the Apple store cause of my ipad air 2 crackling noise issue.
    Before going, i'm going to restore the device as new, in case they'll replace it.

    the question is... are the data REALLY erased with this procedure or could them be recovered in some ways? there are softwares that promise to recover deleted data from ipad/iphones on the internet (never used, maybe they don't work), could it be done on an ipad just restored as new?

    for pcs, low level format (not simple format) grants real deletion of data... what about ios devices? can one be sure that his privacy is granted when returning them?

    thank you, and sorry if this argument has already been discussed.
  2. Gav2k macrumors G3


    Jul 24, 2009
    Yes it's really erased and to read a flash chip after this process would require equipment beyond most people's means.
  3. ipaddaro thread starter macrumors regular

    Dec 6, 2014

    Thank you for the answer.
    Anyway, do you think that Apple (of course) or anyone working in an Apple store (this is the real concern) could have such equipment?
    i know that we have to trust in Apple's privacy policy, and that it's a very reliable company... but so this is the only way to delete the data and still not lose the warranty?
  4. Gav2k macrumors G3


    Jul 24, 2009
    No they don't. You have to physically remove the memory chips from the pcb then have the equipment to hook that chip up to a computer to recover the data. Your talking 10's of thousands in equipment just to read the chip.
  5. Intell macrumors P6


    Jan 24, 2010
    Even with the NAND chip removed, all data on the device is encrypted. Once restored, the encryption keys are destroyed rendering any data on the NAND chip useless and inaccessible.
  6. ipaddaro thread starter macrumors regular

    Dec 6, 2014
    thank you guys! ;)
    i think your answers solved my question...
  7. rigormortis, Dec 29, 2014
    Last edited: Dec 29, 2014

    rigormortis macrumors 68000


    Jun 11, 2009
    gav2k isn't totally correct on this.

    ever since the iPhone 3gs and iOS 3 came out, all iPhones have had hardware encryption and large chunks of the iPhone disk is fully encrypted.

    the iPhone contains a block cipher in that encrypts and decrypts your iPhone in what apple calls "effaceable storage" meaning storage that apple believes cannot be retrieved at all.

    the encryption is 256 bit.

    even if you did do what gav2k says, it would be "computationally impossible" to decrypt the iPhone's storage using brute force methods in the known lifetime of a human being or a the age of the universe.

    if you use an unlock code, it automatically encrypts everything. this is a standard feature with iOS that cannot be turned off. the only way to turn off encryption is not to use a lock code

    the lock screen introduces delays when you try and brute force someone's iPhone. it can also disable the iPhone too. because of these delays it can take 5 years to brute force someone's locks screen if you set it to 6 characters (like abc123).

    brute forcing the lock screen requires physical access to the device. it has to be in your hand. it can't be done over a usb port, like ANDROID

    the only ways to retrieve data off of an erased iPhone is :
    1) get the persons computer that is running itunes and go after their itunes.
    2) hack the persons iCloud account
    3) jail break the iPhone.. once you jail break the phone, maybe it can access the keys, but apple says it not possible. maybe this was in iOS 8 or maybe before iOS 7 u could access the keys.

    BluRay security would of been practically hard to crack if we didn't have the keys. that is why dvd and bluray can be copied, is because we have the keys.

    if you wanted to break AES-256, which the iPhone uses, and guessed 100 trillion guesses per second, it would take you 6.22 thousand trillion trillion trillion centuries to get into that iPhone , and that is IN ADDTION to what gav2k says

    another way to put it is if you wanted to retrieve the erased data on an iPhone in someone's reasonable lifetime, maybe you would need 6.22 thousand trillion trillion trillion supercomputers.

    as long as the key does not get out through jailbreaking, or a weakness is discovered in AES, your erased iPhone is protected.

    for more information , please see the iOS white paper at

    apple says that no software or firmware can access these keys so i might be wrong about jail breaking being able to copy them
  8. Gav2k macrumors G3


    Jul 24, 2009
    This is all very true. The reason I didn't go into the encryption side is the op was referring to apple which in all honesty we don't know what tricks they have up there sleeves for recovering data off there own devices lol
  9. ipaddaro thread starter macrumors regular

    Dec 6, 2014
    amazing how many things i learn on this forum... wow!

    just to know if i understood well... the encription code changes the moment i change the password?

    for example, i use 4 numbers passcode, the minimum standard of security.
    if i want to i improve it before restoring it, is it only sufficient that i set a more complex code before the restore? the modify is applied simply doing this?
  10. rigormortis macrumors 68000


    Jun 11, 2009
    it bugs me when android people say we have to catch up, when they do not have hardware encryption at all. until their 5.0 version just came out. and even then , i think its all done in software on android


    google feels that encryption slows down your "android experience" and chooses it to not enable it by default
  11. Gav2k macrumors G3


    Jul 24, 2009
    Says a lot for software optimisation
  12. scaredpoet, Dec 29, 2014
    Last edited: Dec 29, 2014

    scaredpoet macrumors 604


    Apr 6, 2007
    Some do, some don't. There are multiple encryption keys in use. Some are tied to the hardware and do not change (the idea here is that if a thief takes the memory chips from one iPhone and move them to another iPhone, the files are inaccessible, even if you have the right passcode). Others change every time you wipe the device and restore. Still others are "tangled" with your passcode, so when you change your passcode, how the encryption keys are accessed change a bit, too.

    To get the full description, go to page 9 of the iOS security document, which is where it goes into detail about encryption.

    The short answer is: Yes, a more complex passcode means you have a more secure level of protection on your phone. And if you have TouchID on your iPhone, then there's even less of a reason to have a simple 4-digit passcode.

    The long answer: It's complicated. The encryption keys themselves probably won't change, but that doesn't necessarily make data on the phone less secure. The weakest link is always the passcode itself: There's no point for an attacker to try to guess a 256-bit AES key, when it's a lot easier to guess a 4-digit passcode. So, the more complex your passcode, the harder it becomes for that attacker to be successful.

    Even a 20-character complex passcode would probably be statistically easier to try and brute-force than to guess at the "weakest" 256-bit key, so an attacker is always going to try the passcode first, and that's why having complexity to it is important.

    And, if you have your phone set up right, there's only 10 chances at guessing the passcode before the phone is wiped and any hope of data recovery is lost.
  13. ipaddaro thread starter macrumors regular

    Dec 6, 2014
    thank you!
    so, at the end, i think the weakest ring of the chain is the backup on the pc, considering that in most cases data are accessible simply having the hard disk without the need of a password (and data are not encrypted in windows by default)...

    i restored my devices very few time (only when a major os is released).. having the backup is sufficient for restoring it or apple id password is needed? i think i was always asked to put the password, but i'm not sure...

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