Re: Time Expiry Alogorithm??

[Andrew Farmer <andfarm () teknovis com>]

On 23 Nov 2004, at 15:02, Florian Weimer wrote:
> * Andrew Farmer:
> > Especially considering that there aren't enough atoms in the universe 
> > to
> > store all that precalculated data, nor enough energy to do all the
> > calculations.
>
> Typically, such estimates ignore the possibilities of quantum
> superpositions.

On the other hand, we have yet to create a practical quantum computer.

> > (Schneier says that there's enough energy in a supernova to do about
> > 2^224 operations on a 100% efficient computer. And remember that AES
> > or PGP take multiple operations to calculate results...)
>
> Schneier's estimates are wrong.  They are based on the incorrect
> assumption that all bit operations are irreversible and
> entropy-increasing.  There is no hard evidence that this is true in
> general.

On the other hand, we have yet to discover a way to circumvent the 
second
law of thermodynamics.

If quantum computing comes through (and I doubt it will), we'll all 
start
using quantum encryption. Until then, 256 bits is good enough for me.

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