[Q]:Generate Unique ID's

[Steve Holden]

"Mel Wilson" <mwilson at the-wire.com> wrote in message
news:1mX1+ks/KzOY089yn at the-wire.com...
> In article <mailman.1054097983.30587.python-list at python.org>,
> Tim Peters <tim.one at comcast.net> wrote:
> >The latter for me.  If you're worried about the inconsequentially
unikely,
> >then as Knuth points out, if you have a truly random source and suck
random
> >bits out of it, every now and again you're going to get a billion zeroes
in
> >a row.  Most applications of RNGs would be devastated by such an
occurrence
> >(e.g., trying xor'ing a billion zeroes into plaintext as a means of
> >encryption).  OTOH, for most PRNGs it's possible to prove that will never
> >happen.  Excepting bugs, of course, and again the HW and SW going into
> >physical RNGs isn't immune to bugs either.
>
>    But you have to consider your attackers' point of view.
> There are lots of sequences that will make ciphertext that
> looks just like unaltered plaintext but, taken naively at
> face value, says things that are not true.  By the time your
> random source produces a billion zeroes, it will probably
> already have treated the attackers to several of these other
> sequences, and they'll be very wary about believing what
> they see.
>

That little word "probably" is problematic, of course. The probability that
the *apparently unaltered* texts are generated before the random number
generator produces its list of a billion zeroes would be what, exactly?

don't-argue-randomness-with-the-timbot-ly y'rs -  steve
--
Steve Holden                                  http://www.holdenweb.com/
Python Web Programming                 http://pydish.holdenweb.com/pwp/