[Cryptography] recommending ChaCha20 instead of RC4 (RC4 again)

[dan at geer.org]

Jerry, you wrote a longish item which ends with this memory-jog:

 | Yes, performance matters.  It always has:  A system that's secure only
 | as long as it operates below the data rates necessary to get the job
 | it's paid to do done isn't secure in any meaningful sense.  We've been
 | lulled by years of being able to make raw single-stream performance (and
 | ever-increasing memory usage, and ever-growing disk usage) Someone
 | Else's Problem, which miraculously Someone Else has solved for us. 
 | Those days are over.  It's *our* problem now.

If the above is a lemon, what kind of lemonade might we make of it?

So many things come to mind.  Were the average person to stop buying
new toys that happen to come with new operating systems which happen
to allow their makers to stop upgrading that part of their customer
base that hasn't plumped for the latest gear...  (I've got a long
diatribe about taking by eminent domain widely used codebases that
are abandoned by their putative owners.)

But to your main point that technology advances that have the effect
of making cheap an absence of attentive engineering are themselves
ending -- that really might be a good thingk and a good thing we
should think about now just like now is the time to think about
cryptography post-quantum.  The paper below(*) hints at this in a
different direction, viz., that resource constraint on converting
algorithms to metal may also soonish appear.

--dan



(*)
www.pnas.org/content/early/2013/11/27/1312752110.full.pdf#page=1&view=FitH

On the materials basis of modern society 
T. E. Graedel1, E. M. Harper, N. T. Nassar, and Barbara K. Reck 
School of Forestry and Environmental Studies, Center for Industrial
Ecology, Yale University, New Haven, CT 06511 
Edited by William C. Clark, Harvard University, Cambridge, MA, and
approved October 11, 2013 (received for review July 29, 2013) 

It is indisputable that modern life is enabled by the use of materials
in its technologies. Those technologies do many things very well,
largely because each material is used for purposes to which it is
exquisitely fitted. The result over time has been a steady increase
in product performance. We show that this materials complexity has
markedly increased in the past half-century and that elemental life
cycle analyses characterize rates of recycling and loss. A further
concern is that of possible scarcity of some of the elements as
their use increases. Should materials availability constraints
occur, the use of substitute materials comes to mind. We studied
substitution potential by generating a comprehensive summary of
potential substitutes for 62 different metals in all their major
uses and of the performance of the substitutes in those applications.
As we show herein, for a dozen different metals, the potential
substitutes for their major uses are either inadequate or appear
not to exist at all. Further, for not 1 of the 62 metals are exemplary
substitutes available for all major uses. This situation largely
decouples materials substitution from price, thereby forcing material
design changes to be primarily transformative rather than incremental.
As wealth and population increase worldwide in the next few
decades, scientists will be increasingly challenged to maintain and
improve product utility by designing new and better materials, but
doing so under potential constraints in resource availability.