2
$\begingroup$

I recently heard that in Linux, /dev/random and /dev/urandom are pseudo random number generators but not true random number generator.

So I am curious to know the difference between pseudo & true random number? In other words What is the difference between pseudo-randomness & true-randomness?

$\endgroup$
  • 7
    $\begingroup$ This could largely be answered by a Google search. Do you have a more specific question about this related to computational science? $\endgroup$ – horchler Mar 25 '16 at 15:07
  • $\begingroup$ @horchler If this question is more suitable on other (SE) site (example-Unix & Linux) then tell/suggest me $\endgroup$ – Pandya Mar 29 '16 at 5:09
  • $\begingroup$ Wikipedia article Pseudorandom number generator $\endgroup$ – Steve May 26 '16 at 10:51
2
$\begingroup$

Most random numbers are in fact pseudo-random: they use a seed that is fed to a perfectly deterministic algorithm which can then generate series of numbers which are periodic but with a very large and complicated period so they usually appear random.

This has drawbacks of course since it's not really random, but also advantages, among which is reproducibility: if you store the seed, using this seed again will give you the exact same list of "random" numbers...

Here are a few links as well as another to a source of real random numbers

$\endgroup$
  • 2
    $\begingroup$ Conversely, for certain applications (generation of cryptographic keys, picking winning lottery numbers, etc.) it's very important that the output of a random number generator be unpredictable. In cryptographic applications it's common to combine actual physically random numbers with a pseudorandom number generator to produce unpredicatable output. $\endgroup$ – Brian Borchers Apr 26 '16 at 2:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.