DRBG-0.1.2: A deterministic random bit generator (aka RNG, PRNG) implementing DRBGs from NIST SP 800-90




This module is the convenience interface for the DRBG (NIST standardized number-theoretically secure random number generator). Everything is setup for using the crypto-api CryptoRandomGen type class. For example, to seed a new generator with the system secure random (System.Crypto.Random) and generate some bytes (stepping the generator along the way) one would do:

    gen <- newGenIO :: IO HashDRBG
    let Right (randomBytes, newGen) = genBytes 1024 gen

Selecting the underlying hash algorithm is supporting using *DRBGWith types:

    gen <- newGenIO :: IO (HmacDRBGWith SHA224)

Composition of generators is supported using two trivial compositions, GenXor and GenAutoReseed. Additional compositions can be built by instanciating a CryptoRandomGen as desired.

    gen <- newGenIO :: IO (GenBuffered (GenAutoReseed (GenXor AesCntDRBG (HashDRBGWith SHA384)) HmacDRBG))



type HmacDRBG = State SHA512Source

An alias for an HMAC DRBG generator using SHA512.

type HashDRBG = State SHA512Source

An Alias for a Hash DRBG generator using SHA512.

type HmacDRBGWith = StateSource

The HMAC DRBG state (of kind * -> *) allowing selection of the underlying hash algorithm (SHA1, SHA224 ... SHA512)

type HashDRBGWith = StateSource

The Hash DRBG state (of kind * -> *) allowing selection of the underlying hash algorithm.

data GenXor a b Source

g :: GenXor a b generates bytes with sub-generators a and b and exclusive-or's the outputs to produce the resulting bytes.

data GenAutoReseed a b Source

g :: GenAutoReseed a b is a generator of type a that gets automatically reseeded by generator b upon every 32kB generated.

reseed g ent will reseed both the component generators by breaking ent up into two parts determined by the genSeedLength of each generator.

genBytes will generate the requested bytes with generator a and reseed a using generator b if there has been 32KB of generated data since the last reseed. Note a request for > 32KB of data will be filled in one request to generator a before a is reseeded by b.

genBytesWithEntropy will push the entropy into generator a, leaving generator b unchanged unless the count hits 32KB, in which case it is reseeds a (for a second time) using b as in normal operation via genBytes.

data GenBuffered g Source

g :: GenBuffered a is a generator of type a that attempts to maintain a buffer of random values size >= 1MB and <= 5MB at any time.