How would I go about this? I don't want to roll my own but I do really want to use SCRYPT as a KDF for several algorithms, some of which require an output length longer than the SHA-256 hash. Otherwise with encryption algorithms like AES-256 it's the perfect size already.
Do I just manipulate the keylength of the second PBKDF2 output? If I'm correct, this technically wouldn't be SCRYPT anymore but just a close variant?
Would it be at all practical to use the SCRYPT hashing algorithm as the PRF in HKDF or PBKDF2 output?
I understand how to use it as an authentication hash but as a full fledged KDF perhaps I don't have the right code and documentation is extremely unclear to me.