Early boot, activation, upgrades

[C. Scott Ananian]

On 7/10/07, C. Scott Ananian <cscott at cscott.net> wrote:
> The AES encryption on the Geode is spec'ed at 40MiB/sec.  Using a
> fixed key converts AES into a hash function which is over 50x faster
> than what we've got.

I take this back, partially: the Geode AES is geared towards bulk
encryption with a fixed key.  Although my copy of Applied Crypto is at
home, hash-using-block cipher algorithms rekey often (see
http://en.wikipedia.org/wiki/Hash_functions_based_on_block_ciphers and
its footnote 1).  I couldn't immediately find cycle breakdowns for
rekeying on the Geode, but it's reasonable to assume that we can't
quite hash at 40MiB/s.  However, the 50x factor gives us plenty of
room to play with, and the Geode AES interface lets us pipeline the
two halves of an MDC-2 implementation (
http://eprint.iacr.org/2006/294.pdf ).  It may be of academic interest
to implement and benchmark AES-128/MDC-2 now that I've got an XO, but
from what I'm hearing our hash algorithms are already pretty much set
in stone.
 --scott

-- 
                         ( http://cscott.net/ )