Re: Fermi estimates

2014-11-15 Thread MFPA
-BEGIN PGP SIGNED MESSAGE- Hash: SHA512 Hi On Friday 14 November 2014 at 3:01:59 PM, in mid:54661967.30...@nordnet.fr, Philip Jackson wrote: Does he have to pause between each iteration to see if he has 'something good' ? Could, presumably, stop after several iterations to check

Re: Fermi estimates

2014-11-14 Thread Pete Stephenson
On Fri, Nov 14, 2014 at 10:25 AM, Johan Wevers joh...@vulcan.xs4all.nl wrote: On 14-11-2014 3:15, Robert J. Hansen wrote: 10**38 attempts at 10**6 bitflips per attempt equals 10**44 bitflips total. At carpet-scuffing power, that's about 10**15 joules of energy, [...] But to make our

Re: Fermi estimates

2014-11-14 Thread Philip Jackson
On 14/11/14 03:36, Robert J. Hansen wrote: Whoops! so 10**30 years. The universe is about 10 billion years old, or 10**13 years, so ... our brute-force key cracker takes 10**17 times longer than the age of the universe in order to brute-force a 128-bit key. 10 billion is 10**10, so it

Re: Fermi estimates

2014-11-14 Thread Robert J. Hansen
Thanks for that (and the previous) It makes the brain hurt but raises a few questions in my mind. The real purpose of a Fermi estimate isn't to give you solid answers: it's to give you an appreciation of the problem. If it does that, it's done its job. (Also, a listmember named Ineiev

Re: Fermi estimates

2014-11-14 Thread Johan Wevers
On 14-11-2014 16:01, Philip Jackson wrote: Does anything prevent the key breaker getting lucky and cracking it first try? No. It's just extremely unlikely. It seems to me that all discussions on key breaking with their very large numbers always assume that the last try is THE ONE. Nu,

Fermi estimates

2014-11-13 Thread Robert J. Hansen
A while ago Hauke asked if the statement in the FAQ about a brute-forcer leaving the Earth uninhabitable was correct. I said it was, but I didn't break out the math. Now that I have a few minutes to breathe, here's the full answer. It's a Fermi estimate, which means it's not going to be

Re: Fermi estimates

2014-11-13 Thread Robert J. Hansen
Whoops! so 10**30 years. The universe is about 10 billion years old, or 10**13 years, so ... our brute-force key cracker takes 10**17 times longer than the age of the universe in order to brute-force a 128-bit key. 10 billion is 10**10, so it takes 10**20 times the age of the universe. But