iPhone Encryption and Factory Reset

[JulesJam]

AIUI, if you have a fingerprint unlock or passcode unlock set up, when you do a factory reset the encryption keys are erased meaning that the info is still on your device but it is encrypted and the encryption keys are no longer recoverable so no one can ever access the info.

If I am wrong in my understanding, please correct me.

Also AIUI, if you don't have a fingerprint or passcode unlock set up and do a factory reset, the information on the device is recoverable, albeit someone would have to have specialized equipment to recover it.


Again, if I am wrong in my understanding, please correct me.

Thanks!

 

[Beenblacklisted]

incorrect , just to do factory reset you would have to bypass the fingerprint/passcode lock. So what you are talking about is a dfu restore which would erase everything and make it like a factory reset.

 

[JulesJam]

incorrect , just to do factory reset you would have to bypass the fingerprint/passcode lock. So what you are talking about is a dfu restore which would erase everything and make it like a factory reset.

Not following you completely. What is the best way to factory reset a device to wipe it completely? I want to sell a device of a relative's and they are concerned about anyone recovering their info.

 

[killawat]

OP you are correct. There USED to be utilities available to do a wipe (by writing a large, random file) but Apple removed the good ones. There may be utilities available to Jailbroken phones for free space wipes.

For the paranoid I would factory erase the phone, restart and upload a file (or multiple files) equal to the free space then do another erase.

 

[Intell]

When a reset or restore is done and a passcode is set, the data is still on the device, but fully encrypted with encryption keys that are no longer in existence. A DFU restore does nothing better or different than a regular iTunes restore.

If you want to completely reset a device, the built is reset function will do that just as well as restoring it in iTunes. Both completely obliterate the media partition leaving nothing behind. As long as you have an passcode on the device, there is no need to attempt to erased the remaining free space.

 

[JulesJam]

When a reset or restore is done and a passcode is set, the data is still on the device, but fully encrypted with encryption keys that are no longer in existence. A DFU restore does nothing better or different than a regular iTunes restore.

If you want to completely reset a device, the built is reset function will do that just as well as restoring it in iTunes. Both completely obliterate the media partition leaving nothing behind. As long as you have an passcode on the device, there is no need to attempt to erased the remaining free space.

But that is only true if you have a fingerprint or passcode unlock set up, correct?

If you never set up a fingerprint or passcode, the info has never been encrypted, correct?

 

[Intell]

It's still encrypted, but with a weaker form as it doesn't have a proper entanglement key like the human generated passcode.

 

[JulesJam]

It's still encrypted, but with a weaker form as it doesn't have a proper entanglement key like the human generated passcode.

Ok so to summarize, the best way is to set up a passcode or fingerprint unlock and then do a factory reset or restore through iTunes?

 

[Intell]

Yes, that is correct. For simplicity, I'd suggest restoring via iTunes.

 

[Applejuiced]

When a reset or restore is done and a passcode is set, the data is still on the device, but fully encrypted with encryption keys that are no longer in existence. A DFU restore does nothing better or different than a regular iTunes restore.

If you want to completely reset a device, the built is reset function will do that just as well as restoring it in iTunes. Both completely obliterate the media partition leaving nothing behind. As long as you have an passcode on the device, there is no need to attempt to erased the remaining free space.

Yes, What he said above.
The way it is handled now in iOS nobody will be able to recover anything that was previously on the phone if you do a restore or erase all command on the device itself.
Unless off course someone like the NSA or other highly advanced cyber hacking group gets a hold of it but what are the odds of that? If you're just selling it you'd be fine either way.

 

[JulesJam]

Phone is running 9.3, does that matter?

 

[Intell]

It does not matter, unless you are promoting it as a jailbreakable iPhone when you try to sell it. That may increase its resale value. If you are, just do the reset on the iPhone itself and do not restore through iTunes.

 

[JulesJam]

It does not matter, unless you are promoting it as a jailbreakable iPhone when you try to sell it. That may increase its resale value. If you are, just do the reset on the iPhone itself and do not restore through iTunes.

Thanks, IME selling on swappa, you don't get more for jailbreakable devices. There really aren't that many people who jailbreak when you compare it to the large numbers of people who use iPhones.

I just wanted to make sure that the encryption situation wasn't any different if you were using an outdated iOS version but really now that I think about it, 9.3 was released not too long ago.