[Gnuk-users] Hardware PIN pad

[NdK]

Il 31/01/2017 09:25, Ineiev ha scritto:

>>> I've just layed out a draft [0]; the device doesn't fit on the top
>>> of FST-01, but I think it could be connected to it with a cable.
>> Why a micro? It could easily be hijacked by an attacker to store the PIN
>> code.
> FST-01 already includes a micro, doesn't it?
Yep. But if it gets tampered, key material is (or should be) lost (IIRC
updating the fw deletes the keys -- but I could be wrong).

>> An MCP23017 (16 IOs) or MCP23008 (8 IOs)
> A micro-based design would be more straightforward programmatically,
> and in theory more flexible (e.g. implementing an encrypted
> connection to FST-01).
I don't think it's more straightforward, since you have to modify both
the fw on the ARM and the one on the secondary micro.
Using an IO expander you don't have to maintain and defend the second
fw. And nowhere to hide a keylogger :)

>> paired with an optional .96"
>> 128x64 I2C OLED display could probably be better.
> 128x64 I2C OLED displays are less readily available; I guess they
> would be considerably less cheap.
About $2.5 on AliExpress for single pieces.
And you would "recycle" the same I2C bus used for communication with the
keyboard controller.

BYtE,
 Diego