cprng-aes and crypto-random replacement

[ibotty]

Hi,

should Crypto.Random.AESCtr be ported to cryptonite or is chacha the proposed replacement?

What about the urandom generator?

Thanks

[vincenthz]

ChaCha is probably a good replacement, but I'm planning to add AESCtr back. it was just thrown under the bus for lack of time. For the urandom generator, yes it's a good idea to add back too.

[ibotty]

After filing the issue I came to understand that the MonadRandom IO instance uses a mix of all entropy sources including urandom. I would be very pleased to have a rng where you can specify what EntropyBackend to use though.

What do you think about the following monad transformer

data SystemRNG e m a = SystemRNG m a

instance EntropySource e => MonadRandom (SystemRNG e)

with a suitable

runSystemRNG :: EntropySource e => proxy e -> SystemRNG e m a -> m a

(or maybe lacking the proxy argument).

[vincenthz]

Some of this is probably a good idea, but I don't think distinguishing the SystemRNG at the type level and exposing the EntropySource is useful. It would make more sense to expose a simple ADT that can combine the EntropySource the way it want, e.g.:

data EntropyType = Cpu | System ...

getEntropyFrom :: EntropyType -> ...