"Jim C. Nasby" <decibel@decibel.org> writes:
> I would think it wouldn't be hard to change the protocol/code so that
> the response from providing an invalid user is the same as providing a
> valid one.
How would you do that? The response for a valid user will (a) include
the same salt on repeated trials (so no generating a random one); (b)
usually be different from the salt given for other usernames (so no
using the same one every time, either) and (c) probably be provided in a
measurably different time from the time taken by any algorithm that
manages to work around (a) and (b).
You could maybe work around (c) by delaying *all* password challenges to
take, say, 100 msec ... but that's hardly what I call a cost-free
solution either.
regards, tom lane