Re: [tlug] Are ordered hashes useful?

[Marty Pauley <marty.pauley@example.com>]

On Sat, Feb 12, 2011 at 1:47 AM, Stephen J. Turnbull <stephen@example.com> wrote:
> Raymond Wan writes:
>
>  > 2)  The other reason is to give a unique key through hashing.  For
>  > security reasons, you probably want the result of hashing to be
>  > different between program runs or between systems or something.
>
> But a hash can't do that, it's a deterministic algorithm and therefore
> always gives the same answer from the same inputs.

But then it's easy to turn that into an algorithm that can be
different between program runs by choosing a random number at the
start of the program and modifying (or "salting") the key with it
before hashing.  If this happens automatically then from the users
point of view it is part of the hashing algorithm.

-- 
Marty