* Move the convert stuff from the node lib to here and implement the encrypt trait for f64
* Do we need the encrypt buffer function? i.e. does it need to handle variable sized inputs? (Siphash returns an int!)
- Get rid of it and just use u64 and f64 etc (JS lib can use a bigint from siphash)
* Make the encrypt implementations specific to the cipher type and don't make CipherText generic on the Cipher (just an array of u8)
- I suppose we could make CT a struct containing the array and some meta
* Implement the Zeroize trait on ORECipher so that we can zeroize it from other crates (on Drop)
## Generics
I reckon the generics should be on the scheme not ORECipher. That is, we could do:
impl ORECipher for OREAES128<N, B>
Then the associated types could still be generic in N and B.