I recently had a comment made to me in an online discussion after I'd stated that randomness in a salt doesn't matter -- and I got the following response:
Salts may not have to be "secure," but the method of generation can matter. Using a cryptographic random data source helps ensure uniqueness and randomness in the salt data. Depending on the algorithm being used, the distribution of randomness in the salt can have bearing on the strength of the key.
Now, in most cases with a 22 character salt (in bcrypt for example) even with a prng the odds of generating the same salt twice are pretty small but its the second bit of that statement -- I'm not sure what that means and I certainly can't say its "wrong" without understanding it ....
So is this correct? Does randomness in a salt matter? Since salts are a known thing if someone's attacking a table of hashes, how can the quality of the salt matter?