"The only hard problem in cryptography is key-management."
All sectors are encrypted with AES in CBC mode using a constant key,
currently compiled in and all zero.
To activate this module, write the magic header on the partition:
echo "<<FreeBSD-GEOM-AES>>" | dd conv=sync of=/dev/md98
The encrypted device will be one sector shorter and have ".aes"
appended to its name.
Sponsored by: DARPA & NAI Labs.