Pat Adams <[EMAIL PROTECTED]> writes:
> On Thu, 2005-08-04 at 14:44 -0500, 2wsxdr5 wrote:
>> There are also several places that you can get a reasonably random
>> number for the seed from your machine. The amount of free disk space,
>> unless that doesn't change much on your machine. The amount of free
>> RAM, (up time mod cpu usage). Any number of things could be used that
>> are not very predictable, if at all.
>
> But again, those aren't truely random. They're random-enough for the
> average web applications. The original poster, if memory serves, asked
> if it was possible to get true random numbers from MySQL. True random
> numbers can't be predicted even if I know everything about your system.
> Because computers are predictable beasts, the random number generators
> that they used are constrained by the hardware limits.
/dev/random is a source of some genuine entropy on many Unix-like
operating systems. It uses variations in system timings that are
believed to be truly random. It's not good for a large volume of
output, but it's a good seed. You could probably incorporate access
to it or its friend /dev/urandom as a UDF:
http://sunsite.mff.cuni.cz/MIRRORS/ftp.mysql.com/doc/en/Adding_UDF.html
EGD (Entropy Gathering Daemon) is an option for other Unix-like
systems:
http://egd.sourceforge.net/
or you can use a Lava Lamp:
http://www.lavarnd.org/index.html
I'm sure Windows has some way to do this, too.
Many systems also have an onboard random number generator which you
should be able to access through an OS driver.
----ScottG.
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