[NIIBE Yutaka] STM32F103 flash ROM read-out service

NdK ndk.clanbo at gmail.com
Thu Jun 7 13:01:55 CEST 2018

Il 07/06/2018 02:26, NIIBE Yutaka ha scritto:

> ... provided it can be manufactured independently with reproducibility
> (as NdK points out in another expression).  I think that dependency to
> specific company matters.
Expecially because you have no control over the finished product: if
they decide to add a backdoor after you vetted the chip, you can't know.
Unless there's a continuous vetting process (over any batch, decap X%
chips to check).

> And... when you use a "secure" chip, how can you measure their claim to
> be "secure"?  In my opinion, it should be possible to be evaluated by
> independent party.
That's usually the "certified" part. Too bad too often they tell a
device is certified against a norm, but they don't tell exactly what got
certified (unless it's mandated by the norm, but that's quite rare).
Was it just hardness against flash reading? What about invasive attacks?
And side-channel ones?
Too often (controllers from Microchip, just to say one) there's note
that the protection only works if the device is used as specified:
ROFLASTC! An attacker will do anything... running it out of spec is the
most basic attack, usually way easier than decapping.

> Furthermore, if some technology is available for a chip to be "secure",
> it is good for users of semiconductor to ask applying the technology to
> improve some other chips.
It's just a matter of costs. If it adds a fraction of a cent to the
cost, it's not suitable for the cheap chips. Probably the
countermeasures needed for "military grade" smartcards add 2-3 cents to
the chip cost (probably less).

> Please make sure it doesn't violate any laws and regulations, if someone
> is going ahead.
Worth verifying, but having *my* secrets extracted from *my* device
should not violate laws. But after that is the extracted data still a
secret at all?

> In my opinion, these things (evaluation how secure a chip is) should be
> possible, in some scientific ways, not only for Gnuk (or for STM32F103),
> but for general cases.
You can choose the standard for having the device certified. And define
the exact attack scenario. Then pay. A lot, usually. :(


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