First note: This is on-disk usage only, never transmitted over a server.
How secure, or additionally secure, is it to sha-3 (512) a password if said password is below 128 characters, THEN proceeding to scrypt it?
Is it more secure than straight scrypting the password? Should beyond 128 be sha-3'd? Should there even be any sha-3ing of it at all?
I'm aware sha-3 is just a hashing and not the same as aes/bcrypt/scrypt/twofish etc., I am merely looking to see if some sort of addition layer can be added for even more security than scrypt offers by default.
On a note of weak password will always be weak, in this instance a file can be specified as the password (of any size within the operational limits of scrypt), but a regular password can be used as well, therefore my question arises:
How much more secure, even in a theoretical sense, if it all, is sha3-512-ing a password below 128 characters, and above 128 characters, before scrypt-ing it?