* [DONE] Random Number Generator

RNG is needed for Data Encryption Key to encrypt private key (P and Q).
It is important to collect enough entropy.  Perhaps, it would
be possible to get entropy from USB traffic (of other devices).


* [Mostly DONE] RSA

It would be good not to use malloc.


* Flash ROM recover from unexpected shutdown during write


* [DONE] configure support

configure script would be good to select a board and to generate
random serial number.


* [DONE] Random number update

Implemented using SECECT_FILE and UPDATE_BINARY command, which is not
in the OpenPGP card specification.

Old description: Currently, Gnuk doesn't have random number generator,
but use random bytes calculated by hosts.  After Gnuk uses random
number, the entry in Flash ROM will be cleared.  Some scheme to update
random number bytes is needed.  Possibly, private Data Objects, or by
another SELECT FILE.


* [DONE] Manufacture ID

Get it from FSFE.


* [DONE] Serial number

The AID of the card contains serial number.  It should be unique.  USB
serial number should be unique to identify different tokens, too.


* [DONE] Flash ROM garbage collection


* [DONE] Flash ROM protection

Flash ROM can be protected with OpenOCD.  DfuSe users should know that
the content can be accessible by DfuSe, even if we enable read
protection of flash ROM.  For proper protection, don't use DfuSe but
use OpenOCD to write and protect.