[Cryptography] information, Shannon, and quantum mechanics
Dave Horsfall
dave at horsfall.org
Thu Feb 26 12:25:07 EST 2015
On Wed, 25 Feb 2015, Jerry Leichter wrote:
> I had done a back-of-the-envelope estimate and came up with a QM limit
> for K of somewhere between 128 and 256. I later asked a physicist I
> knew, and he did a more accurate estimate. It turns out that this
> hypersphere could do about 2^315 bit flips - and store about 2^315 bits
> of information. So AES-256 "can be broken in principle" in 100 years by
> brute force - but you don't need to make the keys all that much larger
> to eliminate that possibility. :-)
For the morbidly curious, my trusty HP-42S says it's 6.67E94 (that's a
pretty big number, as numbers go); I'm not game enough to fire up "bc" on
my Unix/Linux/Mac boxen to get all the figures...
--
Dave Horsfall DTM (VK2KFU) "Bliss is a MacBook with a FreeBSD server."
http://www.horsfall.org/spam.html (and check the home page whilst you're there)
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