So I've been reading about salt, and am confused about why the length is so critical. From my understanding salt is used for protection against pre-computed attacks.
Say I have a single password that is hash with salt length
n. Suppose this hash and salt is accessible to the attacker. My questions are as follow:
nis too short, is the problem that a pre-computed rainbow table may already exist?
nis long enough that a pre-computed rainbow table doesn't exist, what function does a longer salt serve? A brute force attack would simply add the
nlength salt to each hash it's generating. 50 bit
n, 500 bit
n. No difference, because the salt is known and simply added to all the brute force password values being hashed.
So to summarize, when trying to crack a single salted password hash, as long as
n is long enough that a rainbow table doesn't exist, then the salt length
n adds no security to the hashed password. Is this true?