3 ms·
> Salting a standard cryptographic hash (like SHA2) doesn't do anything meaningful to slow a brute force attack. Sure, but it does at least prevent the use of
by michaelmior 3y ago
> Salting a standard cryptographic hash (like SHA2) doesn't do anything meaningful to slow a brute force attack.
Sure, but it does at least prevent the use of rainbow tables. Arguably not relevant in this scenario, but it doesn't mean that salting does nothing. Rainbow tables can speed up attacks by many orders of magnitude. Salting may not prevent each individual password from being brute forced, but for most attackers, it probably will prevent your entire database from being compromised due to the amount of computation required.
- tptacek 3y agoRainbow tables don't matter. If you're discussing the strength of your scheme with or without rainbow tables, you have already lost. https://news.ycombinator.com/item?id=38098188 https://news.ycombinator.com/item?id=38098188
- robertlagrant 3y agoThat's just a link where you claim the same thing. What's your actual rationale? Do you think salting is pointless?
- tptacek 3y agoI think it's meaningless. Every password KDF is randomized. But randomization isn't what makes them difficult to brute-force; non-password-KDF "salted" hashes are extremely easy to brute force, which is the whole reason we have password KDFs. "Salted hashes" are one of the more treacherous security cargo cults, because they create the impression that the big problem you have to solve hashing a password is somehow mixing in a salt. No: just doing that by itself doesn't accomplish anything meaningful at all.
- robertlagrant 3y agoUnderstood, but I think this is just people using "hash" and "KDF" interchangeably. Agree that a KDF is the way to go, but salting it is also a good idea to explode the search space.
- michaelmior 3y agoI don't follow your point. Yes, you can brute force. But if I have 50,000 unsalted password hashes, I can crack those using rainbow tables much faster than brute forcing all 50,000. For a single password hash, I agree it probably doesn't really matter.
- juliusdavies 3y agoI don't understand why anyone would ever have 50,000 or even 1 unsalted password hash.