[FDE] MultiCore Comparisons

[dan at geer.org]

catchall at princesshouse.co.uk writes:
 | Dear Sirs,
 | 
 | The one major drawback that I can see all software based solutions is
 | the overhead on the CPU.
 | 


I've wondered that as well.  As I read the tea leaves,
the doubling time for CPU is, per Moore's Law, 18 months
but circa 12 months for disk.  Ipso facto, the ratio of
CPU to disk in a constant-dollar design regime must fall
at the rate of an order of magnitude per decade, or a
CAGR for the inverse ratio of disk/CPU of 26%/annum.
For the CPU side to keep up, either the fraction of total
retained data actually handled per unit time has to fall,
or the number and/or percentage of CPUs devoted to encryption
must rise.  I suspect this drives the encryption into the
disk enclosure quite inexorably.

--dan