[dependenttypes]

Please justify why hashing a high entropy password should have a high cost. I can't see any benefit arising from this. If anything you lose entropy if you use something like pbkdf due to cycles.

[0x0]

Because it slows down anyone looking to crack/reverse the passwords? The only thing protecting your high entropy password is the cost of the hash. If you could run infinite attempts in 2 seconds then even your high entropy password would fail.

Anyways, most people don't use high entropy passwords, so there's little point in arguing against this IMHO.

[dependenttypes]

> Because it slows down anyone looking to crack/reverse the passwords?

Good luck brute-forcing through 2^256 passwords. The speed of the hash function should not matter.

If you still want a slow hash function though then just use more rounds.

> The only thing protecting your high entropy password is the cost of the hash

No, not really. It is the fact that the password is high entropy, combined with the preimage resistance of the hash.

> If you could run infinite attempts in 2 seconds then even your high entropy password would fail.

So would your pkdf.