GPG's vulnerability to quantum cryptography

Robert J. Hansen rjh at
Fri May 16 16:07:25 CEST 2014

> Now where did you calculate that from?

Forgot one more reference -- look at Schneier's _Applied Cryptography_,
where he talks about the physical limits of the cosmos.  He has a
physicist's error in his presentation (he's off by a factor of ln 2),
but he confirms the Second Law necessity of a heat pump that would
offset any benefit from running at a lower temperature.

(By "a physicist's error", physicists think of hypothetical computers
that run in base e [2.71828], while computer scientists think of real
ones that run in base 2.  A physicist's hypothetical computer needs kT
joules to clear a nat, while a real computer uses kT ln 2 to clear a
bit.  Schneier's text talks in terms of bits, but he does the math in
terms of nats ... which makes a kind of sense, given he has a graduate
degree in physics.)

Now, can we put this ridiculous talk of "of course we can break the
Second Law!" to rest?

"If someone points out to you that your pet theory of the universe is in
disagreement with Maxwell's equations -- then so much the worse for
Maxwell's equations.  If it is found to be contradicted by observation
-- well, these experimentalists do bungle things sometimes.  But if your
theory is found to be against the second law of thermodynamics I can
give you no hope; there is nothing for it but to collapse in deepest

    -- Arthur Eddington

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