crypto-api 0.2.1 → 0.3

raw patch · 2 files changed

+72/−17 lines, 2 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• Crypto/Random.hs +71/−16
• crypto-api.cabal +1/−1

@@ -20,18 +20,24 @@ -}  module Crypto.Random-	( CryptoRandomGen(..)+	( -- * Basic Interface+	  CryptoRandomGen(..) 	, GenError (..)-	, newGenIO+	  -- * Helper functions and expanded interface+	, splitGen+	  -- * Instances+	, SystemRandom 	) where -import System.Crypto.Random (getEntropy)+import System.Crypto.Random import Crypto.Types import Control.Monad (liftM) import qualified Data.ByteString as B+import qualified Data.ByteString.Lazy as L import Data.Tagged import Data.Bits (xor, setBit, shiftR, shiftL, (.&.)) import Data.List (foldl')+import System.IO.Unsafe(unsafeInterleaveIO)  -- |many generators have these error conditions in common data GenError =@@ -40,6 +46,7 @@ 	| RangeInvalid		-- ^ When using @genInteger g (l,h)@ and @logBase 2 (h - l) > (maxBound :: Int)@. 	| NeedReseed		-- ^ Some generators cease operation after too high a count without a reseed (ex: NIST SP 800-90) 	| NotEnoughEntropy	-- ^ For instantiating new generators (or reseeding)+	| NeedsInfiniteSeed	-- ^ This generator can not be instantiated or reseeded with a finite seed (ex: 'SystemRandom')   deriving (Eq, Ord, Show)  -- |A class of random bit generators that allows for the possibility of failure,@@ -98,19 +105,67 @@ 	-- can result in an error (`NotEnoughEntropy`). 	reseed		:: B.ByteString -> g -> Either GenError g --- |Use "System.Crypto.Random" to obtain entropy for `newGen`.-newGenIO :: CryptoRandomGen g => IO g-newGenIO = go 0-  where-  go 1000 = error "The generator instance requested by newGenIO never instantiates (1000 tries).  It must be broken."-  go i = do-	let p = Proxy-	    getTypedGen :: (CryptoRandomGen g) => Proxy g -> IO (Either GenError g)-	    getTypedGen pr = liftM newGen (getEntropy $ proxy genSeedLength pr)-	res <- getTypedGen p-	case res of-		Left _ -> go (i+1)-		Right g -> return (g `asProxyTypeOf` p)+	-- |By default this uses "System.Crypto.Random" to obtain entropy for `newGen`.+	newGenIO :: IO g+	newGenIO = go 0+	  where+	  go 1000 = error "The generator instance requested by newGenIO never instantiates (1000 tries).  It must be broken."+	  go i = do+		let p = Proxy+		    getTypedGen :: (CryptoRandomGen g) => Proxy g -> IO (Either GenError g)+		    getTypedGen pr = liftM newGen (getEntropy $ proxy genSeedLength pr)+		res <- getTypedGen p+		case res of+			Left _ -> go (i+1)+			Right g -> return (g `asProxyTypeOf` p)++-- |get a random number generator based on the standard system entropy source+getSystemGen :: IO SystemRandom+getSystemGen = do+        ch <- openHandle+        let getBS = unsafeInterleaveIO $ do+                bs <- hGetEntropy ch ((2^15) - 16)+                more <- getBS+                return (bs:more)+        liftM (SysRandom . L.fromChunks) getBS++-- |Not that it is technically correct as an instance of 'CryptoRandomGen', but simply because+-- it's a reasonable engineering choice here is a CryptoRandomGen which streams the system randoms. Take note:+-- +--  * It uses the default definition of 'genByteWithEntropy'+--+--  * 'newGen' will always fail!+--+--  * 'reseed' will always fail!+--+--  * the handle to the system random is never closed+data SystemRandom = SysRandom L.ByteString++instance CryptoRandomGen SystemRandom where+        newGen _ = Left NeedsInfiniteSeed+        genSeedLength = Tagged 0+        genBytes req (SysRandom bs) =+                let reqI = fromIntegral req+                    rnd = L.take reqI bs+                    rest = L.drop reqI bs+                in if L.length rnd == reqI+                        then Right (B.concat $ L.toChunks rnd, SysRandom rest)+                        else Left $ GenErrorOther "Error obtaining enough bytes from system random for given request"+        reseed _ _ = Left NeedsInfiniteSeed+	newGenIO = getSystemGen++-- | While the safety and wisdom of a splitting function depends on the properties of the generator being split,+-- several arguments from informed people indicate such a function is safe for NIST SP 800-90 generators.+-- (see libraries@haskell.org discussion ~ Sept, Oct 2010)+splitGen :: CryptoRandomGen g => g -> Either GenError (g,g)+splitGen g = do+	let e = genBytes (genSeedLength `for` g) g+	case e of+		Left e -> Left e+		Right (ent,g') -> +			case newGen ent of+				Right new -> Right (g',new)+				Left e -> Left e  -- |Obtain a tagged value for a particular instantiated type. for :: Tagged a b -> a -> b

@@ -1,5 +1,5 @@ name:           crypto-api-version:        0.2.1+version:        0.3 license:        BSD3 license-file:   LICENSE copyright:      Thomas DuBuisson <thomas.dubuisson@gmail.com>, Dominic Steinitz (see Data.LargeWord module)