diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+### 0.1.3.0
+
+* Use [entropy](http://hackage.haskell.org/package/entropy) package for
+  system random generator.
+
 ### 0.1.2.0
 
 * Allow primitive-0.6.
diff --git a/pcg-random.cabal b/pcg-random.cabal
--- a/pcg-random.cabal
+++ b/pcg-random.cabal
@@ -1,5 +1,5 @@
 name:                pcg-random
-version:             0.1.2.0
+version:             0.1.3.0
 synopsis:            Haskell bindings to the PCG random number generator.
 description:
   PCG is a family of simple fast space-efficient statistically good
@@ -41,11 +41,14 @@
     System.Random.PCG.Unique
     System.Random.PCG.Single
   hs-source-dirs:      src
+  ghc-options:         -Wall
   other-extensions:    BangPatterns, CPP, ForeignFunctionInterface
   build-depends:
-    base      >=4.3 && < 5,
-    primitive >=0.4 && < 0.7,
-    random    >=1.0 && < 2.0,
+    base        >=4.3 && < 5,
+    primitive   >=0.4 && < 0.7,
+    random      >=1.0 && < 2.0,
+    bytestring,
+    entropy,
     time
   default-language:    Haskell2010
   cc-options:
diff --git a/src/System/Random/PCG.hs b/src/System/Random/PCG.hs
--- a/src/System/Random/PCG.hs
+++ b/src/System/Random/PCG.hs
@@ -63,9 +63,11 @@
   , uniformBF, uniformBD, uniformBBool
   ) where
 
-import Data.Data
+#if __GLASGOW_HASKELL__ < 710
 import Control.Applicative
+#endif
 import Control.Monad.Primitive
+import Data.Data
 import Foreign
 import GHC.Generics
 import System.IO.Unsafe
diff --git a/src/System/Random/PCG/Class.hs b/src/System/Random/PCG/Class.hs
--- a/src/System/Random/PCG/Class.hs
+++ b/src/System/Random/PCG/Class.hs
@@ -50,19 +50,13 @@
 #include "MachDeps.h"
 #endif
 
-import           Control.Monad
-import           Data.Bits
-import           Data.Int
-import           Data.Word
-import           Foreign               (allocaBytes, peek)
-import           System.IO
-
-import qualified Control.Exception     as E
-import           Data.IORef            (atomicModifyIORef, newIORef)
-import           Data.Ratio            (numerator, (%))
-import           Data.Time.Clock.POSIX (getPOSIXTime)
-import           System.CPUTime        (cpuTimePrecision, getCPUTime)
-import           System.IO.Unsafe      (unsafePerformIO)
+import Control.Monad
+import Data.Bits
+import Data.ByteString (useAsCString)
+import Data.Int
+import Data.Word
+import Foreign         (castPtr, peek)
+import System.Entropy
 
 class Monad m => Generator g m where
   uniform1 :: (Word32 -> a) -> g -> m a
@@ -422,36 +416,15 @@
 
 -- IO randoms
 
-devRandom :: IO Word64
-devRandom =
-  allocaBytes 8 $ \buf -> do
-    nread <- withBinaryFile "/dev/urandom" ReadMode $ \h -> hGetBuf h buf 8
-    when (nread /= 8) $ error "unable to read from /dev/urandom"
-    peek buf
-
--- Acquire seed from current time. This is horrible fall-back for
--- Windows system.
-acquireSeedTime :: IO Word64
-acquireSeedTime = do
-  c <- (numerator . (%cpuTimePrecision)) `liftM` getCPUTime
-  t <- toRational `liftM` getPOSIXTime
-  let n    = fromIntegral (numerator t) :: Word64
-  return $ wordsTo64Bit (fromIntegral c) (fromIntegral n)
-
--- | Get a random number from system source. If \"@\/dev\/urandom@\" is
---   not found return inferior random number from time.
+-- | Generate a random number using 'System.Entropy'.
+--
+--   Use RDRAND if available and XOR with @\/dev\/urandom@ on Unix and
+--   CryptAPI on Windows. This entropy is considered cryptographically
+--   secure but not true entropy.
 sysRandom :: IO Word64
-sysRandom =
-  devRandom `E.catch` \(_ :: E.IOException) -> do
-    seen <- atomicModifyIORef warned ((,) True)
-    unless seen $ E.handle (\(_::E.IOException) -> return ()) $ do
-      hPutStrLn stderr ("Warning: Couldn't open /dev/urandom")
-      hPutStrLn stderr ("Warning: using system clock for seed instead " ++
-                        "(quality will be lower)")
-    acquireSeedTime
-  where
-    warned = unsafePerformIO $ newIORef False
-    {-# NOINLINE warned #-}
+sysRandom = do
+  bs <- getEntropy 8
+  useAsCString bs $ peek . castPtr
 
 uniformRange :: ( Generator g m
                 , Integral a, Bounded a, Variate a
diff --git a/src/System/Random/PCG/Fast.hs b/src/System/Random/PCG/Fast.hs
--- a/src/System/Random/PCG/Fast.hs
+++ b/src/System/Random/PCG/Fast.hs
@@ -64,7 +64,9 @@
   , uniformBF, uniformBD, uniformBBool
   ) where
 
+#if __GLASGOW_HASKELL__ < 710
 import Control.Applicative
+#endif
 import Control.Monad.Primitive
 import Data.Data
 import Foreign
diff --git a/src/System/Random/PCG/Single.hs b/src/System/Random/PCG/Single.hs
--- a/src/System/Random/PCG/Single.hs
+++ b/src/System/Random/PCG/Single.hs
@@ -63,7 +63,9 @@
   , uniformBF, uniformBD, uniformBBool
   ) where
 
+#if __GLASGOW_HASKELL__ < 710
 import Control.Applicative
+#endif
 import Control.Monad.Primitive
 import Data.Data
 import Foreign
diff --git a/src/System/Random/PCG/Unique.hs b/src/System/Random/PCG/Unique.hs
--- a/src/System/Random/PCG/Unique.hs
+++ b/src/System/Random/PCG/Unique.hs
@@ -58,7 +58,9 @@
   , uniformBF, uniformBD, uniformBBool
   ) where
 
+#if __GLASGOW_HASKELL__ < 710
 import Data.Functor
+#endif
 import Foreign
 
 import System.Random.PCG.Class