4 ms·

I think you need to make sure that each user has a unique salt. If you happen to assign me the same salt as another user then either my or their password will

by KayEss 14y ago

I think you need to make sure that each user has a unique salt. If you happen to assign me the same salt as another user then either my or their password will unlock either account and the attacker only needs to guess the weaker of the passwords.

zaroth 14y ago
Absolutely correct. A 'salt' by definition, is always random. For example, you could use a 32-byte salt with scrypt and you would get back a 32-byte hash. Both are equally unlikely to ever collide (see numbers in the article) even with trillions of entries in the table.
- KayEss 14y ago
  With this scheme random isn't quite enough though, it needs to be unique as well doesn't it?
  - dchest 14y ago
    Chances of generating two random 32-byte strings that collide are so tiny that you can as well say that they are unique.
    - brunnsbe 14y ago
      Remember that assumption is the mother of all fuck-ups, although in this case the risk as you say is minimal.
      - dchest 14y ago
        It's not an assumption, it's a fact.
      - yuliyp 14y ago
        Making an assumption that will fail approximately one time in the entire history of the universe is safe.
    - KayEss 14y ago
      For some reason I read that as 32 bits to start with. 32 bytes is a hell of a lot of salt.
- deleted 14y ago
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