Re: QueryPerformanceCounter() -- Better Randomness.

From	moroney@world.std.spaamtrap.com (Michael Moroney)
Newsgroups	comp.os.linux.advocacy, sci.physics, alt.computer.security, comp.sys.mac.system, alt.hacker, alt.privacy.anon-server
Subject	Re: QueryPerformanceCounter() -- Better Randomness.
Date	2015-10-28 16:17 +0000
Organization	The World : www.TheWorld.com : Since 1989
Message-ID	<n0qsem$dgu$2@pcls7.std.com> (permalink)
References	(2 earlier) <chine.bleu-9FF068.13532027102015@88-209-239-213.giganet.hu> <n0or5i$btl$1@dont-email.me> <Jeff-Relf.Me@Oct.27{10.41P.Seattle.2015}> <n0qmbc$8pt$1@pcls7.std.com> <Jeff-Relf.Me@Oct.28{8.28A.Seattle.2015}>

Cross-posted to 6 groups.

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Jeff-Relf.Me <@.> writes:

>Replying to me, you (Michael_Moroney) wrote:
>> > Seriously, _How_ could thermo/quantum randomness be
>> > better than what I've got, on my i7_4790s/Windows_8 PC ? !
>> > How ? !
>> 
>> Any computer algorithm is just pseudorandomness, 
>> "ignorance" as you put it.  
>> 
>> Dig deep enough into the algorithm and you can _predict_ the next
>> value, although doing so can be extremely difficult.
>> 
>> On the other hand, something based on truly random events, such as 
>> radioactive decay, is, well, truly random, if implemented properly.

>Every second, a 64 bit counter on my 4 GigaHz PC,
>QueryPerformanceCounter(), goes up by another 4 billion.

>Use the low bits of that counter to seed srand(),
>and you have a nice array of PSEUDO_random numbers;

As I said, only pseudorandom, not genuinely random.

>no one could predict what's in the array.

>How, pray tell, would that not be good enough ?

"Good enough" depends on what you are up to.  Are you trying to generate
statistical noise for a test, or to encrypt something just so a casual
observer can't see a file/packet of not very significant importance?
Or are you trying to keep the NSA or some foreign government from ever
seeing the contents of a file?  Because if the NSA really wants to, 
they'll figure out your pseudorandom sequence and decrypt your file
just like that.

Remember, computers are deterministic.  I was just talking about someone
about using the computer's cycle counter to test memory latency in 
different configurations.  For a given configuration, a particular test
of his sees the cycle counter increment by the same amount, as long as 
interrupts, timer etc. are all locked out.

Thread

Better Randomness ? ! Jeff-Relf.Me <@.> - 2015-10-27 22:41 -0700
  Re: Better Randomness ? ! Julio Di Egidio <julio@diegidio.name> - 2015-10-27 22:46 -0700
  Re: Better Randomness ? ! Fabian Russell <root@localhost.localdomain> - 2015-10-28 06:50 +0000
    Re: The pseudo_random array is fully known, 100.0000% predictable. Fabian Russell <root@localhost.localdomain> - 2015-10-28 17:34 +0000
    Re: The pseudo_random array is fully known, 100.0000% predictable. benj <none@gmail.com> - 2015-10-30 05:48 -0400
      Re: The pseudo_random array is fully known, 100.0000% predictable. Fabian Russell <root@localhost.localdomain> - 2015-10-30 18:53 +0000
        Re: The pseudo_random array is fully known, 100.0000% predictable. noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-30 14:08 -0700
          Re: The pseudo_random array is fully known, 100.0000% predictable. Fabian Russell <root@localhost.localdomain> - 2015-10-30 22:36 +0000
            Re: The pseudo_random array is fully known, 100.0000% predictable. "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-11-01 15:14 -0800
  Re: Better Randomness ? ! moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-10-28 14:33 +0000
    Re: Better Randomness ? ! chrisv <chrisv@nospam.invalid> - 2015-10-28 09:36 -0500
      Re: Better Randomness ? ! benj <none@gmail.com> - 2015-10-30 05:56 -0400
    Re: Better Randomness ? ! "Ezekiel" <zeke@nosuchemail.com> - 2015-10-28 10:46 -0400
    QueryPerformanceCounter() -- Better Randomness. Jeff-Relf.Me <@.> - 2015-10-28 08:28 -0700
      Re: QueryPerformanceCounter() -- Better Randomness. "Ezekiel" <zeke@nosuchemail.com> - 2015-10-28 11:48 -0400
        RDRAND has numerous problems. Jeff-Relf.Me <@.> - 2015-10-28 09:35 -0700
      Re: QueryPerformanceCounter() -- Better Randomness. moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-10-28 16:17 +0000
        QueryPerformanceCounter() -- Better Randomness. Jeff-Relf.Me <@.> - 2015-10-28 09:50 -0700
        Re: QueryPerformanceCounter() -- Better Randomness. Fabian Russell <root@localhost.localdomain> - 2015-10-28 17:44 +0000
          Re: QueryPerformanceCounter() -- Better Randomness. moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-10-28 18:01 +0000
            Re: QueryPerformanceCounter() -- Better Randomness. Fabian Russell <root@localhost.localdomain> - 2015-10-28 18:39 +0000
    Re: Better Randomness ? ! Nomen Nescio <nobody@dizum.com> - 2015-10-29 19:38 +0100
      Re: Better Randomness ? ! Tim Streater <timstreater@greenbee.net> - 2015-10-29 19:14 +0000
        Re: Better Randomness ? ! Snit <usenet@gallopinginsanity.com> - 2015-10-29 13:10 -0700
      Re: Better Randomness ? ! Fabian Russell <root@localhost.localdomain> - 2015-10-29 21:36 +0000
        Re: Better Randomness ? ! noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-29 17:24 -0700
          Re: Better Randomness ? ! benj <nobody@gmail.com> - 2015-10-29 21:55 -0400
            Re: Better Randomness ? ! Fabian Russell <root@localhost.localdomain> - 2015-10-30 02:12 +0000
            Re: Better Randomness ? ! Fabian Russell <root@localhost.localdomain> - 2015-10-30 02:18 +0000
  Re: Better Randomness ? ! benj <none@gmail.com> - 2015-10-30 05:45 -0400

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