[Cryptography] Kindle as crypto hardware

[Theodore Ts'o]

On Wed, Dec 04, 2013 at 10:40:25AM -0500, Phillip Hallam-Baker wrote:
> 
> I would not choose an Arduino due to the lack of a display capability. But
> I have certainly been considering the Raspberry Pi which has far more
> capability for essentially the same price.

It is possible to add a display shield for an Arduino:

http://www.dfrobot.com/wiki/index.php/Arduino_LCD_KeyPad_Shield_(SKU:_DFR0009)

Cost:

Arduino Uno R3:   $28.90
LCD Keypad Sheid: $13.90

Total cost:       $42.80

> But the cost of a Kindle is $69 including shipping for the device and
> display combined. That is a pretty hard price point to beat. And it is a
> ready to run device rather than a kit. They can be bought off the shelf in
> ready to run condition from numerous retail outlets. So it is pretty easy
> to pin down the potential for compromise.

Sure, althouh the above pricing is for a single unit (and there are
cheaper Arduino's out there, but this one is one of the more
convenient ones to use; if you were creating a large numbers you could
use much cheaper components, but might require more work to assemble
the kit).  Even if you aren't doing a mass production run, you can get
cheaper pricing if you're buying 10+ units.

(BTW, my quick pricing of a Rasberry Pi with a display is not cheaper
than an Arduino, but your milage may vary.)

> The worst case risk they face would be if they are selling the Kindle at
> below cost to make up the difference by selling content. Which might not
> sit well with my type of application where certified destruction of the
> device is a requirement in some ceremonies.

One other nice thing about using your own kit version is that it's
simpler to do certified distruction of only the components that might
contain keying information, and be able to reuse the rest.  It's also
probably easier to create a tamper-proof enclusure with an Arduino
style device compared to using a Kindle.

Cheers,

					- Ted