securely wipe sensitive data from mtd?

securely wipe sensitive data from mtd?

[coreassumption]

What is the proper way to clean a mtd of any sensitive data that may be located on them (NOR and NAND)?

Would flashing a new image via uBoot be enough?  Or would the wear leveling mechanism prevent this from clearing everything?

Would writing 0's from a running OS's be sufficient?  Or is the device 'smart' and not write zero streams?

Are multiple passes of writing suggested or is this just a holdover from myths of magnetic mediums?

Thanks for any insights.

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Re: securely wipe sensitive data from mtd?

[Richard Weinberger]

On Sun, Feb 24, 2019 at 9:04 AM coreassumption
<coreassumption@protonmail.com> wrote:
>
> What is the proper way to clean a mtd of any sensitive data that may be located on them (NOR and NAND)?
>
> Would flashing a new image via uBoot be enough?  Or would the wear leveling mechanism prevent this from clearing everything?
>
> Would writing 0's from a running OS's be sufficient?  Or is the device 'smart' and not write zero streams?

This is not how flash works. You cannot overwrite anything.

> Are multiple passes of writing suggested or is this just a holdover from myths of magnetic mediums?

Well, if you do a block erase the data should be gone. But you can
never be sure that the flash chip really does.
So, like for any other storage type, encrypt the data and throw the
key away. :-)

-- 
Thanks,
//richard

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