[Beowulf] OT: public random numbers?

Michael Di Domenico mdidomenico4 at gmail.com
Thu Aug 11 17:28:11 PDT 2011


How many random numbers per day are you expecting?
If everyone checks at exactly 1pm, should they all see the same
"random" number or should they each get their own "random" number?
What kind of entropy are you expecting on "random"?

On Thu, Aug 11, 2011 at 7:56 PM, David Mathog <mathog at caltech.edu> wrote:
> Since this is very OT, I'll try to keep it short.
>
> Here is the problem - imagine a group of people who neither know nor
> trust each other, yet must agree on the fairness of a single random
> number.  Basically they are going to have a lottery.  They aren't
> organized enough to generate such a number themselves - it must be found
> from some process already active on the web, and be so obviously "fair"
> that they won't argue about that.  Everybody must be able to obtain it
> freely from a web connection.
>
> Can any of you think of a source on the web for a set of small files
> with these properties:
>
> 1.  from a trusted source (here this mostly means the data is generated
>    for some other innocuous purpose)
> 2.  represents a largely random process (temperature readings,
>    stock market values, etc.) with a set generated at known intervals,
>    preferably daily (at least M-F)
> 3.  are never, ever, revised
> 4.  are distributed reliably (for instance, signed files)
> 5.  are publicly and freely available
> 6.  can be obtained reliably (is available from many sites)
>
> So far I have looked at stock market values and weather data - without
> much luck.
>
> You would think the S&P 500 is the S&P 500 and one could look it up on
> any site and get the same data.  Not so! Check the Yahoo and Google
> financial sites for the first few weeks of Jan. 2011 and you will find
> digits that differ between the two sites in every single column.  Not
> every day mind you, but often enough that it isn't reliable.  Heck, the
> volume numbers differ by large factors between the two sites.  So just
> choose one site and go with that?  Not so fast - if the single source
> goes down the data is unavailable, and there is no guarantee that the
> site (which is not party to this particular use of their data) might not
> revise the page or choose to block it entirely.
>
> Or weather data, right?  Lots of random bits there and we trust NOAA.
> But good luck with criteria 3-6.  In particular, they don't give data
> out for free.  In theory no US Government site should, since they are
> supposed to charge to recover distribution costs.
>
> Criteria 4-6 are typical of software distributed on mirror sites, but so
> far I have not found any physical measurements which are distributed in
> a similar manner.
>
> Thanks,
>
> David Mathog
> mathog at caltech.edu
> Manager, Sequence Analysis Facility, Biology Division, Caltech
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