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Old 03-23-2007, 02:45 PM   #1
cwizardone
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Random Seed. What is it?


Recently I noticed my system is saving the "random seed" at shutdown and loading it at start up. I know, in theory, what a random seed is, but here, using Slackware 11 and the 2.6.18 kernel, what is it, what does it do, and why?
Many Thanks.
 
Old 03-23-2007, 03:21 PM   #2
{BBI}Nexus{BBI}
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Read this: http://en.wikipedia.org/wiki/Random_seed
 
Old 03-23-2007, 03:32 PM   #3
XGizzmo
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Truly random numbers are hard to make, there are random functions to make these random numbers.
Those functions use a "random seed" to initialize the random function, The problem is if you use the same seed you get the exact same order of numbers. Think of it as a deck of cards "random seed" shuffles the cards. If you keep the cards in order it will always be in the same order. Only when you shuffle the cards again will the order change. So slackware saves a new random seed every time
so that the random numbers that the random functions create are truly random.

I feel like I need to say random more.
 
Old 03-23-2007, 07:45 PM   #4
bgeddy
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This got me thinking....found this :
http://eprint.iacr.org/2006/086.pdf
.....Heavy stuff..My head hurts !!
 
Old 03-23-2007, 08:39 PM   #5
H_TeXMeX_H
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Random seed is needed because certain programs use it, such as gnupg to generate encryption keys and stuff.

You'd be surprised how difficult it is to get truly random numbers ....
 
Old 03-23-2007, 09:21 PM   #6
syg00
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Quote:
Originally Posted by bgeddy
This got me thinking....found this :
.....Heavy stuff..My head hurts !!
Maybe - but I wish I had that in my hand when I stumbled across some of the relevant code when ambling around the kernel source one day.
No fun trying to work it out for yourself from the source, believe me.
 
Old 03-24-2007, 06:39 AM   #7
bgeddy
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I can imagine.. to quote the paper:

Code:
Why reverse-engineering the LRNG is not easy.
 
  


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