[PYTHON-CRYPTO] Draft hashing PEP

[Rich Salz]

> Yes.  Hmm.. should there be a requires_key variable or function, and a
> key_size value?

Well, presumably you know if you're doing a keyed hash or not, right?

So suppose the init function took a
        with_key=my_key_obj
parameter, where my_key_obj is
        class KeyedHashKey:
                def size(): return 0 # number of bits in the key
                def bits(): return 0 # the actual bits