Get rid of MonadRandom

cardano-crypto-class/src/Cardano/Crypto/VRF/Class.hs

@@ -57,8 +57,6 @@ import Cardano.Binary
           encodeListLen, enforceSize, decodeBytes, encodeBytes,
           withWordSize)
 
-import Crypto.Random (MonadRandom)
-
 import Cardano.Crypto.Util (Empty, bytesToNatural, naturalToBytes)
 import Cardano.Crypto.Seed (Seed)
 import Cardano.Crypto.Hash.Class (HashAlgorithm, Hash, hashRaw)
@@ -111,11 +109,11 @@ class ( Typeable v
   type Signable c = Empty
 
   evalVRF
-    :: (MonadRandom m, HasCallStack, Signable v a)
+    :: (HasCallStack, Signable v a)
     => ContextVRF v
     -> a
     -> SignKeyVRF v
-    -> m (OutputVRF v, CertVRF v)
+    -> (OutputVRF v, CertVRF v)
 
   verifyVRF
     :: (HasCallStack, Signable v a)
@@ -297,12 +295,12 @@ instance (VRFAlgorithm v, Typeable a) => FromCBOR (CertifiedVRF v a) where
       decodeCertVRF
 
 evalCertified
-  :: (VRFAlgorithm v, MonadRandom m, Signable v a)
+  :: (VRFAlgorithm v, Signable v a)
   => ContextVRF v
   -> a
   -> SignKeyVRF v
-  -> m (CertifiedVRF v a)
-evalCertified ctxt a key = uncurry CertifiedVRF <$> evalVRF ctxt a key
+  -> (CertifiedVRF v a)
+evalCertified ctxt a key = uncurry CertifiedVRF $ evalVRF ctxt a key
 
 verifyCertified
   :: (VRFAlgorithm v, Signable v a)

cardano-crypto-class/src/Cardano/Crypto/VRF/Mock.hs

@@ -56,7 +56,7 @@ instance VRFAlgorithm MockVRF where
 
   type Signable MockVRF = ToCBOR
 
-  evalVRF () a sk = return $ evalVRF' a sk
+  evalVRF () a sk = evalVRF' a sk
 
   verifyVRF () (VerKeyMockVRF n) a c = evalVRF' a (SignKeyMockVRF n) == c
 

cardano-crypto-class/src/Cardano/Crypto/VRF/Simple.hs

@@ -25,13 +25,10 @@ import           Numeric.Natural (Natural)
 import           Cardano.Prelude (NoUnexpectedThunks, UseIsNormalForm(..), force)
 import           Cardano.Binary (Encoding, FromCBOR (..), ToCBOR (..))
 
-import           Crypto.Number.Generate (generateBetween)
 import qualified Crypto.PubKey.ECC.Prim as C
 import qualified Crypto.PubKey.ECC.Types as C
-import           Crypto.Random (MonadRandom (..))
 
 import           Data.Word
-import           Data.ByteString (ByteString)
 import qualified Data.ByteString as BS
 import           Data.Bits (shiftL)
 
@@ -101,9 +98,6 @@ h = getHash . hashWithSerialiser @H id
 h' :: Encoding -> Integer -> Point
 h' enc l = pow $ mod (l * (fromIntegral . bsToNat $ h enc)) q
 
-getR :: MonadRandom m => m Integer
-getR = generateBetween 0 (q - 1)
-
 -- | Convert a 'ByteString' into a 'Natural'. Assumes big-endian input.
 bsToNat :: ByteString -> Natural
 bsToNat = bytesToNatBE . BS.unpack
@@ -162,14 +156,15 @@ instance VRFAlgorithm SimpleVRF where
 
   type Signable SimpleVRF = ToCBOR
 
-  evalVRF () a sk@(SignKeySimpleVRF k) = do
+  evalVRF () a sk@(SignKeySimpleVRF k) =
     let u = h' (toCBOR a) k
         y = h $ toCBOR a <> toCBOR u
         VerKeySimpleVRF v = deriveVerKeyVRF sk
-    r <- getR
-    let c = h $ toCBOR a <> toCBOR v <> toCBOR (pow r) <> toCBOR (h' (toCBOR a) r)
+
+        r = fromIntegral (bsToNat y) `mod` q
+        c = h $ toCBOR a <> toCBOR v <> toCBOR (pow r) <> toCBOR (h' (toCBOR a) r)
         s = mod (r + k * fromIntegral (bsToNat c)) q
-    return (OutputVRF y, CertSimpleVRF u (bsToNat c) s)
+    in (OutputVRF y, CertSimpleVRF u (bsToNat c) s)
 
   verifyVRF () (VerKeySimpleVRF v) a (OutputVRF y, cert) =
     let u = certU cert

cardano-crypto-praos/src/Cardano/Crypto/VRF/Praos.hs

@@ -429,12 +429,12 @@ instance VRFAlgorithm PraosVRF where
 
   deriveVerKeyVRF = coerce skToVerKey
 
-  evalVRF = \_ msg (SignKeyPraosVRF sk) -> do
+  evalVRF = \_ msg (SignKeyPraosVRF sk) ->
     let msgBS = serialize' msg
-    proof <- maybe (error "Invalid Key") pure $ prove sk msgBS
-    output <- maybe (error "Invalid Proof") pure $ outputFromProof proof
-    return $ output `seq` proof `seq`
-             (OutputVRF (outputBytes output), CertPraosVRF proof)
+        proof = maybe (error "Invalid Key") id $ prove sk msgBS
+        output = maybe (error "Invalid Proof") id $ outputFromProof proof
+    in output `seq` proof `seq`
+           (OutputVRF (outputBytes output), CertPraosVRF proof)
 
   verifyVRF = \_ (VerKeyPraosVRF pk) msg (_, CertPraosVRF proof) ->
     isJust $! verify pk proof (serialize' msg)

cardano-crypto-tests/src/Test/Crypto/VRF.hs

@@ -11,7 +11,6 @@ module Test.Crypto.VRF
   )
 where
 
-import Cardano.Binary (FromCBOR, ToCBOR (..))
 import Cardano.Crypto.VRF
 import Cardano.Crypto.VRF.Praos
 import Cardano.Crypto.Util
@@ -142,49 +141,45 @@ testVRFAlgorithm _ n =
 
 prop_vrf_verify_pos
   :: forall a v. (Signable v a, VRFAlgorithm v, ContextVRF v ~ ())
-  => TestSeed
-  -> a
+  => a
   -> SignKeyVRF v
   -> Bool
-prop_vrf_verify_pos seed a sk =
-  let (y, c) = withTestSeed seed $ evalVRF () a sk
+prop_vrf_verify_pos a sk =
+  let (y, c) = evalVRF () a sk
       vk = deriveVerKeyVRF sk
   in verifyVRF () vk a (y, c)
 
 prop_vrf_verify_neg
   :: forall a v. (Signable v a, VRFAlgorithm v, Eq (SignKeyVRF v), ContextVRF v ~ ())
-  => TestSeed
-  -> a
+  => a
   -> SignKeyVRF v
   -> SignKeyVRF v
   -> Property
-prop_vrf_verify_neg seed a sk sk' =
+prop_vrf_verify_neg a sk sk' =
   sk /=
     sk' ==>
-    let (y, c) = withTestSeed seed $ evalVRF () a sk'
+    let (y, c) = evalVRF () a sk'
         vk = deriveVerKeyVRF sk
     in not $ verifyVRF () vk a (y, c)
 
 
 prop_vrf_output_size
   :: forall a v. (Signable v a, VRFAlgorithm v, ContextVRF v ~ ())
-  => TestSeed
-  -> a
+  => a
   -> SignKeyVRF v
   -> Property
-prop_vrf_output_size seed a sk =
-  let (out, _c) = withTestSeed seed $ evalVRF () a sk
+prop_vrf_output_size a sk =
+  let (out, _c) = evalVRF () a sk
    in     BS.length (getOutputVRFBytes out)
       === fromIntegral (sizeOutputVRF (Proxy :: Proxy v))
 
 prop_vrf_output_natural
   :: forall a v. (Signable v a, VRFAlgorithm v, ContextVRF v ~ ())
-  => TestSeed
-  -> a
+  => a
   -> SignKeyVRF v
   -> Property
-prop_vrf_output_natural seed a sk =
-  let (out, _c) = withTestSeed seed $ evalVRF () a sk
+prop_vrf_output_natural a sk =
+  let (out, _c) = evalVRF () a sk
       n         = getOutputVRFNatural out
    in counterexample (show n) $
       mkTestOutputVRF n === out
@@ -224,6 +219,5 @@ instance (Signable v Int, VRFAlgorithm v, ContextVRF v ~ ())
   arbitrary = do
     a <- arbitrary :: Gen Int
     sk <- arbitrary
-    seed <- arbitrary
-    return $ withTestSeed seed $ fmap snd $ evalVRF () a sk
+    return $ snd $ evalVRF () a sk
   shrink = const []