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How do computers make up random numbers?

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  • #16
    Originally posted by pablo
    i wonder do they have problem with floating point numbers though
    In a way, they could: just make a bunch of random integers and form the float out of it.
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    • #17
      There is a project that generates random numbers using lava lamps and a webcam. The theory is that the image generated will always have a unique hash value determined by the lava position of say 10 lamps plus the flickering of the light bulbs and therefore you get very good randomness.

      The website seems to be down here is a good article though:

      http://www.wired.com/wired/archive/11.08/random.html
      http://www.almostsmart.com/misc/sig/sig.php

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      • #18
        It's amazing the lengths people go to for random numbers, please could someone give me some examples as to why on Earth this super-randomness is required?

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        • #19
          Originally posted by N9ne
          It's amazing the lengths people go to for random numbers, please could someone give me some examples as to why on Earth this super-randomness is required?
          encryption ?

          same reason why big prime numbers are important.
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          • #20
            And why we need more than 52billion digits of pi.....


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            • #21
              Originally posted by merk
              And why we need more than 52billion digits of pi.....


              Actually we only have 51,539,607,510 decimal digits.
              With the record declared as 51,539,600,000

              Thought, apparently up to 18th iteration, the algorithm used agrees Pi to more than 187 billion digits.

              Go Japan!
              Sig? What sig?

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              • #22
                Originally posted by DarkDelight.net
                Actually we only have 51,539,607,510 decimal digits.
                With the record declared as 51,539,600,000

                Thought, apparently up to 18th iteration, the algorithm used agrees Pi to more than 187 billion digits.

                Go Japan!
                500 million off, not like it matters

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                • #23
                  Originally posted by merk
                  500 million off, not like it matters
                  I'll stick with 3.142

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                  • #24
                    Originally posted by merk
                    500 million off, not like it matters
                    Oh! Looks like you were right in the first place.

                    After a little more digging it seems they broke their own record.

                    206,158,430,163

                    Declared 206,158,430,000
                    Sig? What sig?

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                    • #25
                      Originally posted by pablo
                      encryption ?

                      same reason why big prime numbers are important.
                      Why is it important that the numbers are prime?

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                      • #26
                        Nothing is truelly random in the first place(actually that is arguable, but at least in the non-quantum mechanic world nothing is). One method of producing random numbers once was using lava lamps. Well lava lamps aren't random, set them up each time EXACTLY the same and they will produce the same patterns each time exactly. But in the practical world this doesn't matter as there are so many millions of factors involved in setting up and running a lava lamps that they are as good as random for any purpose.

                        However the truth is that you don't need random numbers at all to have a secure number that can be used in encryption, unique IDs, etc. You just need a number that is based on factors unknown to outsiders who use the system. For example, One number could be the combined birthday dates of 12 employees at the company. This certainly isn't random, but to anyone trying to hack the system by finding what the number is, it is as good as random, because they still have to know what the random number is based on. Which of course, they wouldn't have the slightest clue, if nobody told them it was the birthdays of 12 employees.

                        The only thing important in a "random" number is that there is no pattern between the numbers produced from a given source, and that any factor(IE microseconds, persons birthday) a number is based on cannot be easily determined by an outsider. One number could be the date for a famous persons birthday, another height of the Sears tower, etc. As long he hackers have no clue what these are going to be, it's random to them!

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                        • #27
                          Originally posted by DoST
                          Why is it important that the numbers are prime?
                          Prime numbers, and huge ones at that, are the key to the most secure encryption method (AFAIK) available - RSA. More information here:
                          http://www.muppetlabs.com/~breadbox/txt/rsa.html
                          Chen Avinadav
                          Better to remain silent and be thought a fool than to speak out and remove all doubt.

                          גם אני מאוכזב מסיקור תחרות לתור מוטור של NRG הרשת ע"י מעריב

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                          • #28
                            Chen is that your next idea for hivemail - subatomical radioactive randomness signatures?
                            Dean Clatworthy - Web Developer/Designer

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                            • #29
                              Allegedly, some people (I think SGI) have developed a way to make true random numbers from a camera looking at a lava lamp. A more portable version was a CCD looking at a white noise generator, or something. Not sure. It was on /. a while ago.

                              http://i.ksilebo.com/ksicom_button.png
                              http://i.ksilebo.com/simpli_button.png

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                              • #30
                                Originally posted by Mist
                                Chen is that your next idea for hivemail - subatomical radioactive randomness signatures?
                                I'm already ahead of you - why do you think I'm glowing in the dark?
                                Chen Avinadav
                                Better to remain silent and be thought a fool than to speak out and remove all doubt.

                                גם אני מאוכזב מסיקור תחרות לתור מוטור של NRG הרשת ע"י מעריב

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