shapj@us.ibm.com wrote:
> >If 128 bits isn't big enough for any other reason, then it probably isn't
> >big enough for security. If 128 bits is big enough to make a random
> >collision infeasible, then what other problems might it have?
>
> There are human and mechanical decoding efficiencies in using sparsely
> populated spaces of densely populated clusters. This has nothing at all to
> do with security. Think of it as wanting to prereserve a large enough pool
> of names that you'll never have to grow the pool.
URLs are variable length, so, unlike most traditional unique IDs, you can grow the pool without pain. I don't see a need to choose a length that is sufficient for any more than easily foreseeable demand.
Cheers,
Ben.
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