Cryptonite and bytes

[Ericson2314]

Instead of using an explicit mutable context, and using IO, one can also hide everything in this Monad. I doubt this is better in all cases, but it might be more convenient in some. ekmett/bytes#25

[vincenthz]

bytes doesn't support any of the ByteArrayAccess / ByteArray classes (from memory). Also in some places I need to have exact control on how things are represented/copied for security reason, for example HMAC where the hash need to be done in a specific fashion so as not to have additional copy of your key in memory.

[Ericson2314]

To be clear, I was thinking an additional interface, not replacing the memory classes. Also, while that issue mentioned encryption and hashing, I was thinking mostly about that latter. Specifically, I think https://hackage.haskell.org/package/cryptonite-0.13/docs/Crypto-Hash-IO.html#t:HashAlgorithm is powerful enough for

instance HashAlgorithm h => MonadPut (Hash h) where
  -- ...

There is no HashAlgorithm a => HashAlgorithm (HMAC a) instance, so I am less concerned, but what exactly is the problem here? I'd assume a similarly constructed HMACMonad would have to be eliminated with a key, something like:

runHMACMonad :: (HashAlgorithm a, ByteArrayAccess key) => HMACMonad a -> key -> Digest a