Re: Unique number generation
From: Jean-Luc Cooke (jlcooke_at_engsoc.org)
Date: 2 May 2005 14:05:41 GMT
Tom St Denis <firstname.lastname@example.org> wrote:
> > Unfortunately, not a power of 2, nor even a power of 10. So, if I
> > wanted a number that would appear to be random to someone without
> > knowledge of the key, e.g. equally distributed over the output
> > range, of let's say 0-250000000, what would you suggest then?
> Repeated draws. This has been discussed on sci.crypt before.
I think he wants to invert his numbers back to a sequence # as well tom.
That's is problem.
He wants to issue random IDs, and later be able to verify them for
valitiy without a lookup database.
In short, his design goals arn't in lign with security. The parking
meters in Ottawa have the same problem. They issue smart cards that
help you save carrying change, but the meters don't talk back to home
base to verify the smart card is valid. You can just:
dd if=/dev/smartcard1 of=myFullSC.img
And once you've spent your $25 on the SCard, you:
dd if=myFullSC.img of=/dev/smartcard1
And bob's your uncle.