>he can get a head start in generating rainbow tables against your database. While it is true that he can get a head start, a head start is quite useless becau

>he can get a head start in generating rainbow tables against your database. While it is true that he can get a head start, a head start is quite useless because the work necessary to reverse one hash is independent of the work necessary to reverse a different hash. That means that you still have to brute force each password individually.