[Gnuk-users] Reproducibility of the board and copying flash

[NIIBE Yutaka]

Hello,

While I did the development for Allwinner H3, I considered a technical
possibility for Gnuk.


* Background

When I designed FST-01 (the reference board), I did my best so that it
could be reproducible by anyone.  This is an important point for me to
store my own private keys.

However, I realized that some people around "opensource hardware"
don't share this idea and most products are not reproducible by third
parties.

For example, the Orange Pi PC is called "opensource hardware".  Yes,
there are many technical information is available and we have running
u-boot and Linux with source code.  But... Looking closer, I realized
that the initial boot0 is only available as binary and some important
technical information like DRAM controller and power management is
behind the wall.

For me, the point is how I can control my own computing.


* Copying problem

Copying is easy.  I'd like to encourage to copy the design of FST-01.

However, if it will become easy to copy an instance of Gnuk Token with
private keys, our private keys will be in dainger.


* Changing each instance?

Suppose we include the chip-id of STM32F103 for the computation of DEK
(data encryption key).  Then, the flash image of the chip is only valid
with the paticular instance of STM32F103.

When some kid manage to copy an instance of Gnuk Token, it won't work
as expected.


I know that the scenario above is a bit strange (if we can copy, we
can have the raw data, but the scenario assumes that data itself is
not available).

The question of mine is: should we include the chip-id of STM32F103
for the computation of DEK?

Currently, it's not included.
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