[Cryptography] best practices considered bad term

[Peter Gutmann]

Bill Frantz <frantz at pwpconsult.com> writes:

>Well, there are some important differences between best practices in security
>and the NEC. The NEC has the force of law for one. When I first started doing
>electrical work I was fortunate to find a version of the code which had been
>annotated with the reasons for the provisions, very useful for my style of
>learning.

The value of an electrical code (and in fact any code) depends greatly on how
it's written.  For example the one I'm familiar with:

http://www.med.govt.nz/energysafety/documents/legislation-policy/electricity-act-regulations-codes/standards-and-codes-of-practice/NZECP%2035%201993%20New%20Zealand%20Electrical%20Code%20of%20Practice%20for%20Power%20System%20Earthing%20%20-%20Published%2018%20March%201993%20.pdf

says (among other things) for earth electrodes:

  The type and embedded depth of the earth electrodes shall be such that soil
  drying and freezing will not increase the earth resistance of the earth
  electrodes above the required value. Where practicable, the earth electrodes
  shall be embedded below permanent moisture level, except for electrodes
  which are used for gradient control.

  The design of the electrode shall take into consideration the type,
  emperature and moisture content of the soil as well as the magnitude and
  duration of expected current flow so as to minimise soil dryness in the
  vicinity of the electrodes.

  The material and total cross -sectional area of the earth electrodes shall
  be such as to provide a conductance of not less than that of the earthing
  conductor.

  The design, selection of materials, and construction of the earth electrodes
  shall take into consideration the possible deterioration and increase of
  resistance due to corrosion over the expected period of use of the
  installation.

  In areas where corrosion is likely to be severe, the electrodes shall be of
  hard drawn copper, copper clad or stainless steel, or other metal of such a
  nature or so treated as to be not less resistant to corrosion than hard
  drawn copper, or copper clad or stainless steel.

  In areas where corrosion is not severe, galvanised or plain steel electrodes
  may be used.

Note the emphasis on function rather than form, it outlines a set of
parameters and says you need to operate within them rather than saying "you
need to bury a nickel-plated 20mm copper rod 2m into the soil".  There's no
explicit rationale, but it's made pretty clear why each requirement is the way
it is.

>And, of course, the best practices NEC will probably result in a house that
>doesn't have enough electrical outlets.

Or you end up perpetuating a bad decision made decades earlier, and having to
kludge around it for the rest of eternity.  I'm thinking of ring mains in the
UK (created to save copper after WWII, and a PITA ever since), and the analogy
to X.509 (created to secure OSI directories, ditto).

Peter.