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Groups > comp.programming > #5623
| From | Walter Banks <walter@bytecraft.com> |
|---|---|
| Newsgroups | comp.programming |
| Subject | Re: What happened to radtard? |
| Date | 2015-08-12 14:03 -0400 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <mqg1q1$mek$1@speranza.aioe.org> (permalink) |
| References | <4758eb21-711c-4701-9cbc-d0c4f9be0dee@googlegroups.com> <mpfg4k$8e6$1@dont-email.me> <63eea4a6-2bd2-48f1-879b-19ac5c063ca9@googlegroups.com> <mpflq9$s7b$1@dont-email.me> <mpsjn3$vqk$1@dont-email.me> |
On 05/08/2015 5:08 AM, David Brown wrote: > On 31/07/15 13:24, Richard Heathfield wrote: >> On 31/07/15 12:07, Paul N wrote: >> >> <snip> >> >>> If the data were truly random, you'd expect about the same amount >>> of each byte, so if there is a big difference between the most >>> and least fequent values that would sugest that there's >>> *something* going on. >> >> That's right. Thing is, "about the same amount of each byte" is a >> bit nebulous, isn't it? I'm not quite sure how to express this, but >> I want to be able to decide, in a binary (yes/no) fashion, whether >> there's *something* going on, in a programmatic or at least >> numerical way. How much something does there need to be (how much >> departure from a flat distribution) before it's *something* rather >> than just something? >> > > Of course, even with different frequencies for different bytes, it > could be a random process (think of rolling two dice and adding them, > for a simple example). > > The first step, I think, would be to draw two graphs - one ordered > by frequency, and one ordered by byte. That might give you some > inspiration. > > But without any more information, or a clear outstanding pattern, > it's a lost cause. There is no way from what you have that you > could distinguish line noise from a gzip'ed Shakespear play. > > Probably a bit late jumping in here. You are on the right track with > two graphs - one ordered by frequency, Even distributions can be misleading. I have done enough Monte Carlo simulations to have experienced the need for random numbers with a satistically known distributions. The NSA has patents on pulling out text buried in jpg images. I would think you will need to spend some serious time looking at the algorithms. w..
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What happened to radtard? Chad <cdalten@gmail.com> - 2015-07-31 02:26 -0700
Re: What happened to radtard? Richard Heathfield <rjh@cpax.org.uk> - 2015-07-31 10:47 +0100
Re: What happened to radtard? Paul N <gw7rib@aol.com> - 2015-07-31 04:07 -0700
Re: What happened to radtard? Richard Heathfield <rjh@cpax.org.uk> - 2015-07-31 12:24 +0100
Re: What happened to radtard? David Brown <david.brown@hesbynett.no> - 2015-08-05 11:08 +0200
Re: What happened to radtard? Walter Banks <walter@bytecraft.com> - 2015-08-12 14:03 -0400
Re: What happened to radtard? Paul N <gw7rib@aol.com> - 2015-08-05 15:29 -0700
Re: What happened to radtard? leif.roar@dimnakorr.com - 2015-08-06 03:31 -0500
Re: What happened to radtard? fir <profesor.fir@gmail.com> - 2015-07-31 08:10 -0700
Re: What happened to radtard? Chad <cdalten@gmail.com> - 2015-07-31 23:05 -0700
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