Password Hashes, Again

[Vlad Dascalu]

> I don't think that's true. At least not without knowing the salt first.

If he got access to the DB the assumption is that he knows the code
for the salt (i.e. constant value or first two letters of the password
being tried).

> Surely salting means you can only attack one password at once, whereas not salting means you can attack them all in parallel?

Salting has nothing to do with GPU parallelism. bcrypt fails on GPUs
because it requires a long memory area which exceeds the addressable
cache of the GPU units  (see this answer:
http://crypto.stackexchange.com/questions/400/why-cant-one-implement-bcrypt-in-cuda
).