3GS Secure wipe

[AAPLaday]

Hey just a quick question. Im selling my 16GB 3GS iPhone and having done a secure wipe by 'erase all content and data' it only took a few seconds. When i had my 1st gen Touch it took over an hour. After reading up on this its because as opposed to rewriting over the files on the older models, it actually removes the encryption key to access these files.

I am therefore assuming these files are still located on the iPhone but no longer accessible. Now after further searching its claimed that someone could quite easily jailbreak my phone and access the old logs containing my un-zeroed data. I wonder if anyone could confirm this and also if this is true would i be better off writing over the memory with video files to clear it?

Thanks in advance

 

[pcs are junk]

no it erases like every other ipod/iphone. this erases faster because this is the 3GS, it uses the 3G network, and the S stands for speed. its processor is better than any of the ipod touches or any other iphones.

 

[muxa-]

no it erases like every other ipod/iphone. this erases faster because this is the 3GS, it uses the 3G network, and the S stands for speed. its processor is better than any of the ipod touches or any other iphones.

a mistake in most of the points made:
1) 3GS erases just the crypto key, which decrypts data on the fly. Thats why it's such a quick erase, in comparison to 3G. There are some rumors that it's possible to recover the data after such erase - but it's next to impossible for a regular user.
2) iPod Touch 3G is faster than iPhone 3GS. iPhone 3GS CPU is down-clocked to 600mhz in comparison to Touch 3G 800mhz

 

[AAPLaday]

Thanks for the input. I have wiped it now and hope thats enough. Got offered 80 percent of the price i bought it for and back in july i only had enough to get the 16GB version. I can now get the 32 or wait till june for new ones

 

[CocoaPuffs]

Thanks for the input. I have wiped it now and hope thats enough. Got offered 80 percent of the price i bought it for and back in july i only had enough to get the 16GB version. I can now get the 32 or wait till june for new ones

Sounds like you got ripped off. Since selling the first generation iPhone, I haven't sold one that isn't for profit.

As for secure wipe, I would do a DFU restore to be safe.

 

[AAPLaday]

Sounds like you got ripped off. Since selling the first generation iPhone, I haven't sold one that isn't for profit.

As for secure wipe, I would do a DFU restore to be safe.

Cheers, will do. Normally i would agree with you about the price but my mate dropped it few weeks back and it has nasty scratch on bottom of silver bezel.

 

[thelatinist]

As for secure wipe, I would do a DFU restore to be safe.

DFU restore won't do anything that a normal restore doesn't.

 

[AAPLaday]

DFU restore won't do anything that a normal restore doesn't.

So then a normal crypto key wipe would be secure enough?

 

[CocoaPuffs]

DFU restore won't do anything that a normal restore doesn't.

That might be true, but DFU restore ensures that the OS doesn't load prior to the restore, which seems cleaner.

 

[thelatinist]

That might be true, but DFU restore ensures that the OS doesn't load prior to the restore, which seems cleaner.

It makes absolutely no difference. None.

 

[NathanA]

That might be true, but DFU restore ensures that the OS doesn't load prior to the restore, which seems cleaner.

The OS doesn't load prior to the restore with either an iBoot restore or a DFU restore. An iBoot restore, by definition , is conducted by iBoot, the higher-level bootloader that LLB kicks off. The OS hasn't loaded by that point. Bootstrapping the OS boot is iBoot's job.

The only reason DFU exists is to allow you to conduct a restore if iBoot (or the entire NOR for that matter) is trashed. DFU restore mode is basically the same restore code that is in iBoot, except it's permanently burned into ROM. DFU mode is what gives the iPhone (and iPod Touch) its reputation as being "unbrickable" by software...even if the NOR and the NAND contain only 0s, you can still load firmware on the device without breaking open the hardware and decoupling the flash chips from the mainboard and/or using a JTAG. And because DFU exists in ROM/silicon and can't be modified or overwritten, it's always there to bail you out.

All that having been said, though, I think iTunes conducts less "sanity checks" on the restore process if it is being conducted by DFU, so a certain subset of errors that you might get during restore (which usually happen on account of software modification to the phone/jailbreaking, or a jailbreak gone bad) can sometimes be bypassed by using DFU mode to load on stock firmware.

I wonder if the "DFU makes for a cleaner restore" and "DFU mode has to be used to wipe off traces of a jailbreak" myths came about because the Pwnage jailbreak requires users to use DFU to load on the initial jailbroken, custom IPSW. The only reason that is a requirement for the Pwnage 'sploit is because the DFU code in the bootrom is where the bug that is being exploited resides. (And it's nice having it there, because any phones manufactured with that bug cannot be patched in software by Apple. Wish an equivalent bug had been found in the 3GS by this point.)

-- Nathan