How difficult is it to break the OpenPGP 40 character long fingerprint?

Robert J. Hansen rjh at
Mon Apr 1 23:06:23 CEST 2013

On 04/01/2013 01:46 PM, Daniel Kahn Gillmor wrote:
> Predicting computing power or the state of mathematics itself 100 or
> 1000 years into the future seems like a dubious proposition.

Yes and no.  We're not going to get around the Margolus-Levitin limit
(you can't flip a bitstate in faster than h/4E seconds, where E is the
amount of energy you're using) unless we first figure a way around the
Heisenberg Uncertainty Principle, for instance [*].  We're not getting
around the Landauer Bound (establishes a minimum energy for information
erasure) unless someone repeals the Second Law of Thermodynamics [**].
And we're not getting around the Bekenstein limit (establishes a maximum
density for information storage) period full-stop, as near as physics
can tell us.

We have a lousy track record at predicting the rate of technological
advancement, but we have a pretty good track record at discovering
fundamental limits of the universe.

[*]   Okay, so Margolus-Levitin doesn't say energy *precisely*, it can
technically be any conserved quantity.

[**]  Adiabatic computing may offer a way around this, but it's unknown
whether the laws of physics will allow true adiabatic computing to even

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