Am I misunderstanding what a hash salt is?

Question

I am working on adding hash digest generating functionality to our code base. I wanted to use a String as a hash salt so that a pre-known key/passphrase could be prepended

Answer 1

Its worth mentioning that even though the salt should be different for each password usage, your salt should in NO WAY be computed FROM the password itself! This sort of thing has the practical upshot of completely invalidating your security.