[Cryptech Tech] Status tamper detection and MKM erasure

[Linus Nordberg]

Linus Nordberg <linus at nordberg.se> wrote
Wed, 18 May 2016 12:52:15 +0200:

> Next up is lowering power consumption in idle mode (disable unused
> functions, use interrupts instead of busy-looping) and speed up erasure
> (write in "sequential mode") and implementing some kind of POST function
> in collaboration with the FPGA and the ARM.

I just pushed some code to user/ln5/tamper. From commit message:

    Do wipe MKM when tamper is detected, sleep when not.
    
    Writing the MKM in "sequential mode" (a.k.a. "burst") but still
    busy-waiting for confirmation of SPI write operation being done.
    Would using an interrupt be faster?
    
    Sleeping is done in "power down mode". There are less sleepy modes
    which presumably consume more power but might wake up quicker. A good
    start would be to figure out how long time it takes to wake up from
    power down.

It'd great if the FPGA could verify that the MKM is indeed full of
zeroes after the button has been pressed. Joachim?