Securely erase an Android device?

[Snickerzz]

Wanting to sell my old phone so I want to securely erase the storage. I figured something like Roadkill's Diskwipe would work fine but i'm not sure if it can access the root directory of Android.. any suggestions?

[GreezyJeezy]

root the phone then use a rooted app that can wipe it

[Snickerzz]

Just now, GreezyJeezy said:

root the phone then use a rooted app that can wipe it

That won't overwrite everything since it would require the phone to be either booted or having it run off the app from internal storage.

[Samfisher]

Encrypt and decrypt.  It's the only secure way Google recommends wiping the phone before sale.

[GreezyJeezy]

3 minutes ago, Snickerzz said:

That won't overwrite everything since it would require the phone to be either booted or having it run off the app from internal storage.

idk you could do that and then factory restore it

[Snickerzz]

Just now, GreezyJeezy said:

idk you could do that and then factory restore it

A factory restore still wouldn't securely erase it. 

 

1 minute ago, Samfisher said:

Encrypt and decrypt.  It's the only secure way Google recommends wiping the phone before sale.

Just saw a guide saying that, encrypt then do a factory reset, have a link from Google backing this by any chance?

[ALwin]

Throw it into a vat of red hot molten lava.  I guarantee 101% that the data will not be recoverable.

[GreezyJeezy]

1 minute ago, Snickerzz said:

A factory restore still wouldn't securely erase it. 

 

Just saw a guide saying that, encrypt then do a factory reset, have a link from Google backing this by any chance?

thats why you use a rooted app to clear the stuff a factory wont and then factory restore it. i mean do you have like super personal stuff on it? it really should be a big deal.

[Samfisher]

6 minutes ago, Snickerzz said:

A factory restore still wouldn't securely erase it. 

 

Just saw a guide saying that, encrypt then do a factory reset, have a link from Google backing this by any chance?

I'll try finding it but it's by definition a full wipe.  Encrypting data creates a key that is needed to access anything, and decrypting it after that deletes the key and makes the stored data useless.  There's no way to get the data back.

 

If you want, this is the paper that started this investigation into factory resets not being enough :

http://www.cl.cam.ac.uk/~rja14/Papers/fr_most15.pdf

 

[Snickerzz]

4 minutes ago, GreezyJeezy said:

thats why you use a rooted app to clear the stuff a factory wont and then factory restore it. i mean do you have like super personal stuff on it? it really should be a big deal.

It's not specific apps I want gone, it's everything. When you delete something like a photo, it's not actually deleted. Just the reference to it is gone which tells the OS that the space is now free to be overwritten. Stuff like that can still be accessed by software if it wasn't overwritten. The phone as had Steam, bank, skype, facebook, etc accounts logged onto it and other person data that i'd like some random person on ebay to not have. 

 

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