Or put another way:
http://www.schneier.com/blog/archives/2009/09/the_doghouse_cr.html
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These numbers have nothing to do with the technology of the devices; they are the maximums that thermodynamics will allow. And they strongly imply that brute-force attacks against 256-bit keys will be infeasible until computers are built from something other than matter and occupy something other than space.
http://www.schneier.com/blog/archives/2009/09/the_doghouse_cr.html
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until computers are built from something other than matter and occupy something other than space
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until computers are built from something other than matter and occupy something other than space
