diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index d965adb4..7286ae75 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -108,7 +108,7 @@ jobs:
             stack-yaml: stack-old.yaml
           - resolver: lts-18
             ghc: '8.10.7'
-            stack-yaml: stack.yaml
+            stack-yaml: stack.lts-18.yaml
           - resolver: lts-19
             ghc: '9.0.2'
             stack-yaml: stack-coveralls.yaml
@@ -271,8 +271,10 @@ jobs:
         githubToken: ${{ github.token }}
         install: |
           apt-get update -y
-          apt-get install -y ghc libghc-tasty-smallcheck-dev libghc-tasty-hunit-dev libghc-splitmix-dev curl
+          apt-get install -y git ghc libghc-tasty-smallcheck-dev libghc-tasty-hunit-dev libghc-splitmix-dev curl
         run: |
+          git clone https://github.com/Bodigrim/data-array-byte
+          cp -r data-array-byte/Data .
           ghc --version
           ghc --make -isrc:test-legacy -o legacy test-legacy/Legacy.hs
           ./legacy
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bc2cda35..412a7b5a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,11 +1,27 @@
 # 1.3.0
 
-* Move `thawGen` from `FreezeGen` into the new `ThawGen` type class. Fixes an issue with
-  an unlawful instance of `StateGen` for `FreezeGen`.
-* Add `modifyGen` and `overwriteGen` to the `FrozenGen` type class
-* Add `splitGen` and `splitMutableGen`
-* Switch `randomM` and `randomRM` to use `FrozenGen` instead of `RandomGenM`
-* Deprecate `RandomGenM` in favor of a more powerful `FrozenGen`
+* Add compatibility with recently added `ByteArray` to `base`:
+  [#153](https://github.com/haskell/random/pull/153)
+  * Switch to using `ByteArray` for type class implementation instead of
+    `ShortByteString`
+  * Add `unsafeUniformFillMutableByteArray` to `RandomGen` and a helper function
+    `defaultUnsafeUniformFillMutableByteArray` that makes implementation
+    for most instances easier.
+  * Add `uniformByteArray`, `uniformByteString` and `uniformFillMutableByteArray`
+  * Add `uniformByteArrayM` to `StatefulGen`
+  * Add `uniformByteStringM` and `uniformShortByteStringM`
+  * Deprecate `uniformShortByteString` in favor of `uniformShortByteStringM` for
+    consistent naming and a future plan of removing it from `StatefulGen`
+    type class
+  * Expose a helper function `genByteArrayST`, that can be used for
+    defining implementation for `uniformByteArrayM`
+* Improve `FrozenGen` interface: [#149](https://github.com/haskell/random/pull/149)
+  * Move `thawGen` from `FreezeGen` into the new `ThawGen` type class. Fixes an issue with
+    an unlawful instance of `StateGen` for `FreezeGen`.
+  * Add `modifyGen` and `overwriteGen` to the `FrozenGen` type class
+  * Add `splitGen` and `splitMutableGen`
+  * Switch `randomM` and `randomRM` to use `FrozenGen` instead of `RandomGenM`
+  * Deprecate `RandomGenM` in favor of a more powerful `FrozenGen`
 * Add `isInRange` to `UniformRange`: [#78](https://github.com/haskell/random/pull/78)
 * Add default implementation for `uniformRM` using `Generics`:
   [#92](https://github.com/haskell/random/pull/92)
diff --git a/bench/Main.hs b/bench/Main.hs
index 42fb04f7..cb0c5ba0 100644
--- a/bench/Main.hs
+++ b/bench/Main.hs
@@ -25,6 +25,8 @@ seed = 1337
 main :: IO ()
 main = do
   let !sz = 100000
+      !sz100MiB = 100 * 1024 * 1024
+      genLengths :: ([Int], StdGen)
       genLengths =
         -- create 5000 small lengths that are needed for ShortByteString generation
         runStateGen (mkStdGen 2020) $ \g -> replicateM 5000 (uniformRM (16 + 1, 16 + 7) g)
@@ -243,16 +245,18 @@ main = do
                 sz
             ]
           ]
-        , bgroup "ShortByteString"
-          [ env (pure genLengths) $ \ ~(ns, gen) ->
-              bench "genShortByteString" $
-              nfIO $ runStateGenT gen $ \g -> mapM (`uniformShortByteString` g) ns
-          ]
-        , bgroup "ByteString"
-          [ env getStdGen $ \gen ->
-              bench "genByteString 100MB" $
-              nfIO $ runStateGenT gen $ uniformByteStringM 100000000
-          ]
+        ]
+      , bgroup "Bytes"
+        [ env (pure genLengths) $ \ ~(ns, gen) ->
+            bench "uniformShortByteStringM" $
+            nfIO $ runStateGenT gen $ \g -> mapM (`uniformShortByteStringM` g) ns
+        , env getStdGen $ \gen ->
+            bench "uniformByteStringM 100MB" $
+            nf (runStateGen gen . uniformByteStringM) sz100MiB
+        , env getStdGen $ \gen ->
+            bench "uniformByteArray 100MB" $ nf (\n -> uniformByteArray False n gen) sz100MiB
+        , env getStdGen $ \gen ->
+            bench "genByteString 100MB" $ nf (\k -> genByteString k gen) sz100MiB
         ]
       ]
     ]
diff --git a/random.cabal b/random.cabal
index 47a87c0f..ddcef7d5 100644
--- a/random.cabal
+++ b/random.cabal
@@ -100,6 +100,8 @@ library
         deepseq >=1.1 && <2,
         mtl >=2.2 && <2.4,
         splitmix >=0.1 && <0.2
+    if impl(ghc < 9.4)
+      build-depends: data-array-byte
 
 test-suite legacy-test
     type:             exitcode-stdio-1.0
diff --git a/src/System/Random.hs b/src/System/Random.hs
index 92f31faa..9290d242 100644
--- a/src/System/Random.hs
+++ b/src/System/Random.hs
@@ -20,14 +20,28 @@ module System.Random
 
   -- * Pure number generator interface
   -- $interfaces
-    RandomGen(..)
+    RandomGen
+      ( split
+      , genWord8
+      , genWord16
+      , genWord32
+      , genWord64
+      , genWord32R
+      , genWord64R
+      , unsafeUniformFillMutableByteArray
+      )
   , uniform
   , uniformR
-  , genByteString
   , Random(..)
   , Uniform
   , UniformRange
   , Finite
+  -- * Generators for sequences of pseudo-random bytes
+  , uniformByteArray
+  , uniformByteString
+  , uniformFillMutableByteArray
+  , genByteString
+  , genShortByteString
 
   -- ** Standard pseudo-random number generator
   , StdGen
@@ -45,6 +59,8 @@ module System.Random
 
   -- * Compatibility and reproducibility
   -- ** Backwards compatibility and deprecations
+  , genRange
+  , next
   -- $deprecations
 
   -- ** Reproducibility
@@ -199,6 +215,9 @@ uniformR r g = runStateGen g (uniformRM r)
 -- >>> unpack . fst . genByteString 10 $ pureGen
 -- [51,123,251,37,49,167,90,109,1,4]
 --
+-- /Note/ - This function is equivalet to `uniformByteString` and will be deprecated in
+-- the next major release.
+--
 -- @since 1.2.0
 genByteString :: RandomGen g => Int -> g -> (ByteString, g)
 genByteString n g = runStateGenST g (uniformByteStringM n)
diff --git a/src/System/Random/Internal.hs b/src/System/Random/Internal.hs
index 6724ad34..4c87f18b 100644
--- a/src/System/Random/Internal.hs
+++ b/src/System/Random/Internal.hs
@@ -54,7 +54,6 @@ module System.Random.Internal
   , Uniform(..)
   , uniformViaFiniteM
   , UniformRange(..)
-  , uniformByteStringM
   , uniformDouble01M
   , uniformDoublePositive01M
   , uniformFloat01M
@@ -63,19 +62,31 @@ module System.Random.Internal
   , uniformEnumRM
 
   -- * Generators for sequences of pseudo-random bytes
+  , uniformByteStringM
+  , uniformShortByteStringM
+  , uniformByteArray
+  , uniformFillMutableByteArray
+  , uniformByteString
+  , genByteArrayST
   , genShortByteStringIO
   , genShortByteStringST
+  , defaultUnsafeUniformFillMutableByteArray
+  -- ** Helpers for dealing with MutableByteArray
+  , newMutableByteArray
+  , newPinnedMutableByteArray
+  , freezeMutableByteArray
+  , writeWord8
   ) where
 
 import Control.Arrow
 import Control.DeepSeq (NFData)
 import Control.Monad (when, (>=>))
 import Control.Monad.Cont (ContT, runContT)
-import Control.Monad.IO.Class (MonadIO(..))
+import Control.Monad.Identity (IdentityT (runIdentityT))
 import Control.Monad.ST
-import Control.Monad.ST.Unsafe
-import Control.Monad.State.Strict (MonadState(..), State, StateT(..), runState)
-import Control.Monad.Trans (lift)
+import Control.Monad.State.Strict (MonadState(..), State, StateT(..), execStateT, runState)
+import Control.Monad.Trans (lift, MonadTrans)
+import Data.Array.Byte (ByteArray(..), MutableByteArray(..))
 import Data.Bits
 import Data.ByteString.Short.Internal (ShortByteString(SBS), fromShort)
 import Data.IORef (IORef, newIORef)
@@ -86,6 +97,7 @@ import Foreign.Storable (Storable)
 import GHC.Exts
 import GHC.Generics
 import GHC.IO (IO(..))
+import GHC.ST (ST(..))
 import GHC.Word
 import Numeric.Natural (Natural)
 import System.IO.Unsafe (unsafePerformIO)
@@ -178,15 +190,37 @@ class RandomGen g where
   genWord64R m g = runStateGen g (unsignedBitmaskWithRejectionM uniformWord64 m)
   {-# INLINE genWord64R #-}
 
-  -- | @genShortByteString n g@ returns a 'ShortByteString' of length @n@
-  -- filled with pseudo-random bytes.
+  -- | Same as @`uniformByteArray` `False`@, but for `ShortByteString`.
+  --
+  -- @genShortByteString n g@ returns a 'ShortByteString' of length @n@ filled with
+  -- pseudo-random bytes.
+  --
+  -- /Note/ - This function will be removed from the type class in the next major release as
+  -- it is no longer needed because of `unsafeUniformFillMutableByteArray`.
+  --
   --
   -- @since 1.2.0
   genShortByteString :: Int -> g -> (ShortByteString, g)
   genShortByteString n g =
-    unsafePerformIO $ runStateGenT g (genShortByteStringIO n . uniformWord64)
+    case uniformByteArray False n g of
+      (ByteArray ba#, g') -> (SBS ba#, g')
   {-# INLINE genShortByteString #-}
 
+  unsafeUniformFillMutableByteArray ::
+       MutableByteArray s
+    -- ^ Mutable array to fill with random bytes
+    -> Int
+    -- ^ Offset into a mutable array from the beginning in number of bytes. Offset must
+    -- be non-negative, but this will not be checked
+    -> Int
+    -- ^ Number of randomly generated bytes to write into the array. Number of bytes
+    -- must be non-negative and less then the total size of the array, minus the
+    -- offset. This also will be checked.
+    -> g
+    -> ST s g
+  unsafeUniformFillMutableByteArray = defaultUnsafeUniformFillMutableByteArray
+  {-# INLINE unsafeUniformFillMutableByteArray #-}
+
   -- | Yields the range of values returned by 'next'.
   --
   -- It is required that:
@@ -277,14 +311,28 @@ class Monad m => StatefulGen g m where
     pure (shiftL (fromIntegral h32) 32 .|. fromIntegral l32)
   {-# INLINE uniformWord64 #-}
 
+  -- | @uniformByteArrayM n g@ generates a 'ByteArray' of length @n@
+  -- filled with pseudo-random bytes.
+  --
+  -- @since 1.3.0
+  uniformByteArrayM ::
+       Bool -- ^ Should `ByteArray` be allocated as pinned memory or not
+    -> Int -- ^ Size of the newly created `ByteArray` in number of bytes.
+    -> g -- ^ Generator to use for filling in the newly created `ByteArray`
+    -> m ByteArray
+  default uniformByteArrayM ::
+    (RandomGen f, FrozenGen f m, g ~ MutableGen f m) => Bool -> Int -> g -> m ByteArray
+  uniformByteArrayM isPinned n g = modifyGen g (uniformByteArray isPinned n)
+  {-# INLINE uniformByteArrayM #-}
+
   -- | @uniformShortByteString n g@ generates a 'ShortByteString' of length @n@
   -- filled with pseudo-random bytes.
   --
   -- @since 1.2.0
   uniformShortByteString :: Int -> g -> m ShortByteString
-  default uniformShortByteString :: MonadIO m => Int -> g -> m ShortByteString
-  uniformShortByteString n = genShortByteStringIO n . uniformWord64
+  uniformShortByteString = uniformShortByteStringM
   {-# INLINE uniformShortByteString #-}
+{-# DEPRECATED uniformShortByteString "In favor of `uniformShortByteStringM`" #-}
 
 
 -- | This class is designed for mutable pseudo-random number generators that have a frozen
@@ -382,57 +430,169 @@ splitGen = flip modifyGen split
 splitMutableGen :: (RandomGen f, ThawedGen f m) => MutableGen f m -> m (MutableGen f m)
 splitMutableGen = splitGen >=> thawGen
 
-
-data MBA = MBA (MutableByteArray# RealWorld)
-
-
 -- | Efficiently generates a sequence of pseudo-random bytes in a platform
 -- independent manner.
 --
--- @since 1.2.0
-genShortByteStringIO ::
-     MonadIO m
-  => Int -- ^ Number of bytes to generate
-  -> m Word64 -- ^ IO action that can generate 8 random bytes at a time
-  -> m ShortByteString
-genShortByteStringIO n0 gen64 = do
-  let !n@(I# n#) = max 0 n0
-      !n64 = n `quot` 8
+-- @since 1.3.0
+uniformByteArray ::
+     RandomGen g
+  => Bool -- ^ Should byte array be allocted in pinned or unpinned memory.
+  -> Int -- ^ Number of bytes to generate
+  -> g -- ^ Pure pseudo-random numer generator
+  -> (ByteArray, g)
+uniformByteArray isPinned n0 g =
+  runST $ do
+    let !n = max 0 n0
+    mba <-
+      if isPinned
+        then newPinnedMutableByteArray n
+        else newMutableByteArray n
+    g' <- unsafeUniformFillMutableByteArray mba 0 n g
+    ba <- freezeMutableByteArray mba
+    pure (ba, g')
+{-# INLINE uniformByteArray #-}
+
+-- | Using an `ST` action that generates 8 bytes at a type fill in a new `ByteArray` in
+-- architecture agnostic manner.
+--
+-- @since 1.3.0
+genByteArrayST :: Bool -> Int -> ST s Word64 -> ST s ByteArray
+genByteArrayST isPinned n0 action = do
+  let !n = max 0 n0
+  mba <- if isPinned
+    then newPinnedMutableByteArray n
+    else newMutableByteArray n
+  runIdentityT $ defaultUnsafeUniformFillMutableByteArrayT mba 0 n (lift action)
+  freezeMutableByteArray mba
+{-# INLINE genByteArrayST #-}
+
+-- | Fill in a slice of a mutable byte array with randomly generated bytes. This function
+-- does not fail, instead it adjust the offset and number of bytes to generate into a valid
+-- range.
+--
+-- @since 1.3.0
+uniformFillMutableByteArray ::
+     RandomGen g
+  => MutableByteArray s
+  -- ^ Mutable array to fill with random bytes
+  -> Int
+  -- ^ Offset into a mutable array from the beginning in number of bytes. Offset will be
+  -- clamped into the range between 0 and the total size of the mutable array
+  -> Int
+  -- ^ Number of randomly generated bytes to write into the array. This number will be
+  -- clamped between 0 and the total size of the array without the offset.
+  -> g
+  -> ST s g
+uniformFillMutableByteArray mba i0 n g = do
+  !sz <- getSizeOfMutableByteArray mba
+  let !offset = max 0 (min sz i0)
+      !numBytes = min (sz - offset) (max 0 n)
+  unsafeUniformFillMutableByteArray mba offset numBytes g
+{-# INLINE uniformFillMutableByteArray #-}
+
+defaultUnsafeUniformFillMutableByteArrayT ::
+     (Monad (t (ST s)), MonadTrans t)
+  => MutableByteArray s
+  -> Int
+  -> Int
+  -> t (ST s) Word64
+  -> t (ST s) ()
+defaultUnsafeUniformFillMutableByteArrayT mba offset n gen64 = do
+  let !n64 = n `quot` 8
+      !endIx64 = offset + n64 * 8
       !nrem = n `rem` 8
-  mba@(MBA mba#) <-
-    liftIO $ IO $ \s# ->
-      case newByteArray# n# s# of
-        (# s'#, mba# #) -> (# s'#, MBA mba# #)
-  let go i =
-        when (i < n64) $ do
+  let go !i =
+        when (i < endIx64) $ do
           w64 <- gen64
           -- Writing 8 bytes at a time in a Little-endian order gives us
           -- platform portability
-          liftIO $ writeWord64LE mba i w64
-          go (i + 1)
-  go 0
+          lift $ writeWord64LE mba i w64
+          go (i + 8)
+  go offset
   when (nrem > 0) $ do
+    let !endIx = offset + n
     w64 <- gen64
     -- In order to not mess up the byte order we write 1 byte at a time in
     -- Little endian order. It is tempting to simply generate as many bytes as we
     -- still need using smaller generators (eg. uniformWord8), but that would
     -- result in inconsistent tail when total length is slightly varied.
-    liftIO $ writeByteSliceWord64LE mba (n - nrem) n w64
-  liftIO $ IO $ \s# ->
-    case unsafeFreezeByteArray# mba# s# of
-      (# s'#, ba# #) -> (# s'#, SBS ba# #)
-{-# INLINE genShortByteStringIO #-}
+    lift $ writeByteSliceWord64LE mba (endIx - nrem) endIx w64
+{-# INLINEABLE defaultUnsafeUniformFillMutableByteArrayT #-}
+{-# SPECIALIZE defaultUnsafeUniformFillMutableByteArrayT
+  :: MutableByteArray s
+  -> Int
+  -> Int
+  -> IdentityT (ST s) Word64
+  -> IdentityT (ST s) () #-}
+{-# SPECIALIZE defaultUnsafeUniformFillMutableByteArrayT
+  :: MutableByteArray s
+  -> Int
+  -> Int
+  -> StateT g (ST s) Word64
+  -> StateT g (ST s) () #-}
+
+-- | Efficiently generates a sequence of pseudo-random bytes in a platform
+-- independent manner.
+--
+-- @since 1.2.0
+defaultUnsafeUniformFillMutableByteArray ::
+     RandomGen g
+  => MutableByteArray s
+  -> Int -- ^ Starting offset
+  -> Int -- ^ Number of random bytes to write into the array
+  -> g -- ^ ST action that can generate 8 random bytes at a time
+  -> ST s g
+defaultUnsafeUniformFillMutableByteArray mba i0 n g =
+  flip execStateT g
+    $ defaultUnsafeUniformFillMutableByteArrayT mba i0 n (state genWord64)
+{-# INLINE defaultUnsafeUniformFillMutableByteArray #-}
+
+
+-- | Generates a pseudo-random 'ByteString' of the specified size.
+--
+-- @since 1.3.0
+uniformByteString :: RandomGen g => Int -> g -> (ByteString, g)
+uniformByteString n g =
+  case uniformByteArray True n g of
+    (byteArray, g') ->
+      (shortByteStringToByteString $ byteArrayToShortByteString byteArray, g')
+{-# INLINE uniformByteString #-}
 
 -- Architecture independent helpers:
-io_ :: (State# RealWorld -> State# RealWorld) -> IO ()
-io_ m# = IO $ \s# -> (# m# s#, () #)
-{-# INLINE io_ #-}
 
-writeWord8 :: MBA -> Int -> Word8 -> IO ()
-writeWord8 (MBA mba#) (I# i#) (W8# w#) = io_ (writeWord8Array# mba# i# w#)
+st_ :: (State# s -> State# s) -> ST s ()
+st_ m# = ST $ \s# -> (# m# s#, () #)
+{-# INLINE st_ #-}
+
+ioToST :: IO a -> ST RealWorld a
+ioToST (IO m#) = ST m#
+{-# INLINE ioToST #-}
+
+newMutableByteArray :: Int -> ST s (MutableByteArray s)
+newMutableByteArray (I# n#) =
+  ST $ \s# ->
+    case newByteArray# n# s# of
+      (# s'#, mba# #) -> (# s'#, MutableByteArray mba# #)
+{-# INLINE newMutableByteArray #-}
+
+newPinnedMutableByteArray :: Int -> ST s (MutableByteArray s)
+newPinnedMutableByteArray (I# n#) =
+  ST $ \s# ->
+    case newPinnedByteArray# n# s# of
+      (# s'#, mba# #) -> (# s'#, MutableByteArray mba# #)
+{-# INLINE newPinnedMutableByteArray #-}
+
+freezeMutableByteArray :: MutableByteArray s -> ST s ByteArray
+freezeMutableByteArray (MutableByteArray mba#) =
+  ST $ \s# ->
+    case unsafeFreezeByteArray# mba# s# of
+      (# s'#, ba# #) -> (# s'#, ByteArray ba# #)
+
+writeWord8 :: MutableByteArray s -> Int -> Word8 -> ST s ()
+writeWord8 (MutableByteArray mba#) (I# i#) (W8# w#) = st_ (writeWord8Array# mba# i# w#)
 {-# INLINE writeWord8 #-}
 
-writeByteSliceWord64LE :: MBA -> Int -> Int -> Word64 -> IO ()
+writeByteSliceWord64LE :: MutableByteArray s -> Int -> Int -> Word64 -> ST s ()
 writeByteSliceWord64LE mba fromByteIx toByteIx = go fromByteIx
   where
     go !i !z =
@@ -441,48 +601,53 @@ writeByteSliceWord64LE mba fromByteIx toByteIx = go fromByteIx
         go (i + 1) (z `shiftR` 8)
 {-# INLINE writeByteSliceWord64LE #-}
 
-writeWord64LE :: MBA -> Int -> Word64 -> IO ()
-#ifdef WORDS_BIGENDIAN
-writeWord64LE mba i w64 = do
-  let !i8 = i * 8
-  writeByteSliceWord64LE mba i8 (i8 + 8) w64
+-- On big endian machines we need to write one byte at a time for consistency with little
+-- endian machines. Also for GHC versions prior to 8.6 we don't have primops that can
+-- write with byte offset, eg. writeWord8ArrayAsWord64# and writeWord8ArrayAsWord32#, so we
+-- also must fallback to writing one byte a time. Such fallback results in about 3 times
+-- slow down, which is not the end of the world.
+writeWord64LE :: MutableByteArray s -> Int -> Word64 -> ST s ()
+#if defined WORDS_BIGENDIAN || !(__GLASGOW_HASKELL__ >= 806)
+writeWord64LE mba i w64 =
+  writeByteSliceWord64LE mba i (i + 8) w64
 #else
-writeWord64LE (MBA mba#) (I# i#) w64@(W64# w64#)
-  | wordSizeInBits == 64 = io_ (writeWord64Array# mba# i# w64#)
+writeWord64LE (MutableByteArray mba#) (I# i#) w64@(W64# w64#)
+  | wordSizeInBits == 64 = st_ (writeWord8ArrayAsWord64# mba# i# w64#)
   | otherwise = do
-    let !i32# = i# *# 2#
-        !(W32# w32l#) = fromIntegral w64
+    let !(W32# w32l#) = fromIntegral w64
         !(W32# w32u#) = fromIntegral (w64 `shiftR` 32)
-    io_ (writeWord32Array# mba# i32# w32l#)
-    io_ (writeWord32Array# mba# (i32# +# 1#) w32u#)
+    st_ (writeWord8ArrayAsWord32# mba# i# w32l#)
+    st_ (writeWord8ArrayAsWord32# mba# (i# +# 4#) w32u#)
 #endif
 {-# INLINE writeWord64LE #-}
 
+getSizeOfMutableByteArray :: MutableByteArray s -> ST s Int
+getSizeOfMutableByteArray (MutableByteArray mba#) =
+#if __GLASGOW_HASKELL__ >=802
+  ST $ \s ->
+    case getSizeofMutableByteArray# mba# s of
+      (# s', n# #) -> (# s', I# n# #)
+#else
+  pure $! I# (sizeofMutableByteArray# mba#)
+#endif
+{-# INLINE getSizeOfMutableByteArray #-}
 
--- | Same as 'genShortByteStringIO', but runs in 'ST'.
---
--- @since 1.2.0
-genShortByteStringST :: Int -> ST s Word64 -> ST s ShortByteString
-genShortByteStringST n action =
-  unsafeIOToST (genShortByteStringIO n (unsafeSTToIO action))
-{-# INLINE genShortByteStringST #-}
-
+byteArrayToShortByteString :: ByteArray -> ShortByteString
+byteArrayToShortByteString (ByteArray ba#) = SBS ba#
+{-# INLINE byteArrayToShortByteString #-}
 
--- | Generates a pseudo-random 'ByteString' of the specified size.
---
--- @since 1.2.0
-uniformByteStringM :: StatefulGen g m => Int -> g -> m ByteString
-uniformByteStringM n g = do
-  ba <- uniformShortByteString n g
-  pure $
+-- | Convert a ShortByteString to ByteString by casting, whenever memory is pinned,
+-- otherwise make a copy into a new pinned ByteString
+shortByteStringToByteString :: ShortByteString -> ByteString
+shortByteStringToByteString ba =
 #if __GLASGOW_HASKELL__ < 802
-       fromShort ba
+  fromShort ba
 #else
-    let !(SBS ba#) = ba in
-    if isTrue# (isByteArrayPinned# ba#)
-      then pinnedByteArrayToByteString ba#
-      else fromShort ba
-{-# INLINE uniformByteStringM #-}
+  let !(SBS ba#) = ba in
+  if isTrue# (isByteArrayPinned# ba#)
+    then pinnedByteArrayToByteString ba#
+    else fromShort ba
+{-# INLINE shortByteStringToByteString #-}
 
 pinnedByteArrayToByteString :: ByteArray# -> ByteString
 pinnedByteArrayToByteString ba# =
@@ -495,6 +660,40 @@ pinnedByteArrayToForeignPtr ba# =
 {-# INLINE pinnedByteArrayToForeignPtr #-}
 #endif
 
+-- | Same as 'genShortByteStringIO', but runs in 'ST'.
+--
+-- @since 1.2.0
+genShortByteStringST :: Int -> ST s Word64 -> ST s ShortByteString
+genShortByteStringST n0 action = byteArrayToShortByteString <$> genByteArrayST False n0 action
+{-# INLINE genShortByteStringST #-}
+
+-- | Efficiently fills in a new `ShortByteString` in a platform independent manner.
+--
+-- @since 1.2.0
+genShortByteStringIO ::
+     Int -- ^ Number of bytes to generate
+  -> IO Word64 -- ^ IO action that can generate 8 random bytes at a time
+  -> IO ShortByteString
+genShortByteStringIO n ioAction = stToIO $ genShortByteStringST n (ioToST ioAction)
+{-# INLINE genShortByteStringIO #-}
+
+-- | @uniformShortByteString n g@ generates a 'ShortByteString' of length @n@
+-- filled with pseudo-random bytes.
+--
+-- @since 1.3.0
+uniformShortByteStringM :: StatefulGen g m => Int -> g -> m ShortByteString
+uniformShortByteStringM n g = byteArrayToShortByteString <$> uniformByteArrayM False n g
+{-# INLINE uniformShortByteStringM #-}
+
+-- | Generates a pseudo-random 'ByteString' of the specified size.
+--
+-- @since 1.2.0
+uniformByteStringM :: StatefulGen g m => Int -> g -> m ByteString
+uniformByteStringM n g =
+  shortByteStringToByteString . byteArrayToShortByteString
+    <$> uniformByteArrayM True n g
+{-# INLINE uniformByteStringM #-}
+
 
 -- | Opaque data type that carries the type of a pure pseudo-random number
 -- generator.
@@ -522,8 +721,6 @@ instance (RandomGen g, MonadState g m) => StatefulGen (StateGenM g) m where
   {-# INLINE uniformWord32 #-}
   uniformWord64 _ = state genWord64
   {-# INLINE uniformWord64 #-}
-  uniformShortByteString n _ = state (genShortByteString n)
-  {-# INLINE uniformShortByteString #-}
 
 instance (RandomGen g, MonadState g m) => FrozenGen (StateGen g) m where
   type MutableGen (StateGen g) m = StateGenM g
@@ -629,6 +826,11 @@ instance RandomGen SM.SMGen where
   {-# INLINE genWord64 #-}
   split = SM.splitSMGen
   {-# INLINE split #-}
+  -- Despite that this is the same default implementation as in the type class definition,
+  -- for some mysterious reason without this overwrite, performance of ByteArray generation
+  -- slows down by a factor of x4:
+  unsafeUniformFillMutableByteArray = defaultUnsafeUniformFillMutableByteArray
+  {-# INLINE unsafeUniformFillMutableByteArray #-}
 
 instance RandomGen SM32.SMGen where
   next = SM32.nextInt
diff --git a/src/System/Random/Stateful.hs b/src/System/Random/Stateful.hs
index 0e42cc3c..20474cc6 100644
--- a/src/System/Random/Stateful.hs
+++ b/src/System/Random/Stateful.hs
@@ -28,7 +28,15 @@ module System.Random.Stateful
 
   -- * Mutable pseudo-random number generator interfaces
   -- $interfaces
-  , StatefulGen(..)
+  , StatefulGen
+      ( uniformWord32R
+      , uniformWord64R
+      , uniformWord8
+      , uniformWord16
+      , uniformWord32
+      , uniformWord64
+      , uniformShortByteString
+      )
   , FrozenGen(..)
   , ThawedGen(..)
   , withMutableGen
@@ -45,7 +53,7 @@ module System.Random.Stateful
   -- * Monadic adapters for pure pseudo-random number generators #monadicadapters#
   -- $monadicadapters
 
-  -- ** Pure adapter
+  -- ** Pure adapter in 'MonadState'
   , StateGen(..)
   , StateGenM(..)
   , runStateGen
@@ -54,7 +62,7 @@ module System.Random.Stateful
   , runStateGenT_
   , runStateGenST
   , runStateGenST_
-  -- ** Mutable adapter with atomic operations
+  -- ** Mutable thread-safe adapter in 'IO'
   , AtomicGen(..)
   , AtomicGenM(..)
   , newAtomicGenM
@@ -72,7 +80,7 @@ module System.Random.Stateful
   , applySTGen
   , runSTGen
   , runSTGen_
-  -- ** Mutable adapter in 'STM'
+  -- ** Mutable thread-safe adapter in 'STM'
   , TGen(..)
   , TGenM(..)
   , newTGenM
@@ -86,14 +94,23 @@ module System.Random.Stateful
   , uniformViaFiniteM
   , UniformRange(..)
 
-  -- * Generators for sequences of pseudo-random bytes
+  -- ** Generators for sequences of pseudo-random bytes
+  , uniformByteArrayM
+  , uniformByteStringM
+  , uniformShortByteStringM
+
+  -- * Helper functions for createing instances
+  -- ** Sequences of bytes
+  , genByteArrayST
   , genShortByteStringIO
   , genShortByteStringST
-  , uniformByteStringM
+  , defaultUnsafeUniformFillMutableByteArray
+  -- ** Floating point numbers
   , uniformDouble01M
   , uniformDoublePositive01M
   , uniformFloat01M
   , uniformFloatPositive01M
+  -- ** Enum types
   , uniformEnumM
   , uniformEnumRM
 
@@ -384,7 +401,6 @@ instance (RandomGen g, MonadIO m) => StatefulGen (AtomicGenM g) m where
   {-# INLINE uniformWord32 #-}
   uniformWord64 = applyAtomicGen genWord64
   {-# INLINE uniformWord64 #-}
-  uniformShortByteString n = applyAtomicGen (genShortByteString n)
 
 
 instance (RandomGen g, MonadIO m) => FrozenGen (AtomicGen g) m where
@@ -466,7 +482,6 @@ instance (RandomGen g, MonadIO m) => StatefulGen (IOGenM g) m where
   {-# INLINE uniformWord32 #-}
   uniformWord64 = applyIOGen genWord64
   {-# INLINE uniformWord64 #-}
-  uniformShortByteString n = applyIOGen (genShortByteString n)
 
 
 instance (RandomGen g, MonadIO m) => FrozenGen (IOGen g) m where
@@ -536,7 +551,6 @@ instance RandomGen g => StatefulGen (STGenM g s) (ST s) where
   {-# INLINE uniformWord32 #-}
   uniformWord64 = applySTGen genWord64
   {-# INLINE uniformWord64 #-}
-  uniformShortByteString n = applySTGen (genShortByteString n)
 
 instance RandomGen g => FrozenGen (STGen g) (ST s) where
   type MutableGen (STGen g) (ST s) = STGenM g s
@@ -640,7 +654,6 @@ instance RandomGen g => StatefulGen (TGenM g) STM where
   {-# INLINE uniformWord32 #-}
   uniformWord64 = applyTGen genWord64
   {-# INLINE uniformWord64 #-}
-  uniformShortByteString n = applyTGen (genShortByteString n)
 
 -- | @since 1.2.1
 instance RandomGen g => FrozenGen (TGen g) STM where
@@ -795,17 +808,23 @@ applyTGen f (TGenM tvar) = do
 -- Here is an example instance for the monadic pseudo-random number generator
 -- from the @mwc-random@ package:
 --
+-- > import qualified System.Random.MWC as MWC
+-- > import qualified Data.Vector.Generic as G
+--
 -- > instance (s ~ PrimState m, PrimMonad m) => StatefulGen (MWC.Gen s) m where
 -- >   uniformWord8 = MWC.uniform
 -- >   uniformWord16 = MWC.uniform
 -- >   uniformWord32 = MWC.uniform
 -- >   uniformWord64 = MWC.uniform
--- >   uniformShortByteString n g = stToPrim (genShortByteStringST n (MWC.uniform g))
+-- >   uniformByteArrayM isPinned n g = stToPrim (genByteArrayST isPinned n (MWC.uniform g))
 --
 -- > instance PrimMonad m => FrozenGen MWC.Seed m where
 -- >   type MutableGen MWC.Seed m = MWC.Gen (PrimState m)
--- >   thawGen = MWC.restore
 -- >   freezeGen = MWC.save
+-- >   overwriteGen (Gen mv) (Seed v) = G.copy mv v
+--
+-- > instance PrimMonad m => ThawedGen MWC.Seed m where
+-- >   thawGen = MWC.restore
 --
 -- === @FrozenGen@
 --
diff --git a/stack-coveralls.yaml b/stack-coveralls.yaml
index 6a2143bc..30d15974 100644
--- a/stack-coveralls.yaml
+++ b/stack-coveralls.yaml
@@ -2,4 +2,5 @@ resolver: lts-19.33
 system-ghc: true
 packages:
 - .
-extra-deps: []
+extra-deps:
+- data-array-byte-0.1.0.1@sha256:ad89e28b2b046175698fbf542af2ce43e5d2af50aae9f48d12566b1bb3de1d3c,1989
diff --git a/stack-old.yaml b/stack-old.yaml
index 025127c5..5c749977 100644
--- a/stack-old.yaml
+++ b/stack-old.yaml
@@ -16,3 +16,4 @@ extra-deps:
 - tasty-inspection-testing-0.1@sha256:9c5e76345168fd3a59b43d305eebf8df3c792ce324c66bbdee45b54aa7d2c0ad,1214
 - primitive-0.7.4.0@sha256:89b88a3e08493b7727fa4089b0692bfbdf7e1e666ef54635f458644eb8358764,2857
 - vector-0.12.3.1@sha256:fffbd00912d69ed7be9bc7eeb09f4f475e0d243ec43f916a9fd5bbd219ce7f3e,8238
+- data-array-byte-0.1.0.1@sha256:ad89e28b2b046175698fbf542af2ce43e5d2af50aae9f48d12566b1bb3de1d3c,1989
diff --git a/stack-oldish.yaml b/stack-oldish.yaml
new file mode 100644
index 00000000..06ec8886
--- /dev/null
+++ b/stack-oldish.yaml
@@ -0,0 +1,5 @@
+resolver: lts-18.28
+packages:
+- .
+extra-deps:
+- data-array-byte-0.1.0.1@sha256:2ef1bd3511e82ba56f7f23cd793dd2da84338a1e7c2cbea5b151417afe3baada,1989
diff --git a/stack.lts-18.yaml b/stack.lts-18.yaml
new file mode 100644
index 00000000..320440f4
--- /dev/null
+++ b/stack.lts-18.yaml
@@ -0,0 +1,5 @@
+resolver: lts-18.28
+packages:
+- .
+extra-deps:
+- data-array-byte-0.1.0.1@sha256:ad89e28b2b046175698fbf542af2ce43e5d2af50aae9f48d12566b1bb3de1d3c,1989
diff --git a/stack.yaml b/stack.yaml
index d15416fa..7f9dc000 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,4 +1,4 @@
-resolver: lts-18.28
+resolver: lts-21.17
 packages:
 - .
 extra-deps: []
diff --git a/test/Spec.hs b/test/Spec.hs
index 078d4d0a..95f139ad 100644
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -9,6 +9,7 @@
 module Main (main) where
 
 import Control.Monad (replicateM, forM_)
+import Control.Monad.ST (runST)
 import qualified Data.ByteString as BS
 import qualified Data.ByteString.Short as SBS
 import Data.Int
@@ -17,12 +18,17 @@ import Data.Void
 import Data.Word
 import Foreign.C.Types
 import GHC.Generics
+import GHC.Exts (fromList)
 import Numeric.Natural (Natural)
 import System.Random.Stateful
+import System.Random.Internal (newMutableByteArray, freezeMutableByteArray, writeWord8)
 import Test.SmallCheck.Series as SC
 import Test.Tasty
 import Test.Tasty.HUnit
 import Test.Tasty.SmallCheck as SC
+#if __GLASGOW_HASKELL__ < 804
+import Data.Monoid ((<>))
+#endif
 
 import qualified Spec.Range as Range
 import qualified Spec.Run as Run
@@ -80,6 +86,7 @@ main =
     , runSpec
     , floatTests
     , byteStringSpec
+    , fillMutableByteArraySpec
     , SC.testProperty "uniformRangeWithinExcludedF" $ seeded Range.uniformRangeWithinExcludedF
     , SC.testProperty "uniformRangeWithinExcludedD" $ seeded Range.uniformRangeWithinExcludedD
     , randomSpec (Proxy :: Proxy (CFloat, CDouble))
@@ -125,12 +132,39 @@ byteStringSpec =
         let g = mkStdGen 2021
             bs = [78,232,117,189,13,237,63,84,228,82,19,36,191,5,128,192] :: [Word8]
         forM_ [0 .. length bs - 1] $ \ n -> do
-          xs <- SBS.unpack <$> runStateGenT_ g (uniformShortByteString n)
+          xs <- SBS.unpack <$> runStateGenT_ g (uniformShortByteStringM n)
           xs @?= take n bs
           ys <- BS.unpack <$> runStateGenT_ g (uniformByteStringM n)
           ys @?= xs
     ]
 
+fillMutableByteArraySpec :: TestTree
+fillMutableByteArraySpec =
+  testGroup
+    "MutableByteArray"
+    [ SC.testProperty "Same as uniformByteArray" $
+        forAll $ \isPinned -> seededWithLen $ \n g ->
+          let baFilled = runST $ do
+                mba <- newMutableByteArray n
+                g' <- uniformFillMutableByteArray mba 0 n g
+                ba <- freezeMutableByteArray mba
+                pure (ba, g')
+          in baFilled == uniformByteArray isPinned n g
+    , SC.testProperty "Safe uniformFillMutableByteArray" $
+        forAll $ \isPinned offset count -> seededWithLen $ \sz g ->
+          let (baFilled, gf) = runST $ do
+                mba <- newMutableByteArray sz
+                forM_ [0 .. sz - 1] (\i -> writeWord8 mba i 0)
+                g' <- uniformFillMutableByteArray mba offset count g
+                ba <- freezeMutableByteArray mba
+                pure (ba, g')
+              (baGen, gu) = uniformByteArray isPinned count' g
+              offset' = min sz (max 0 offset)
+              count' = min (sz - offset') (max 0 count)
+              prefix = replicate offset' 0
+              suffix = replicate (sz - (count' + offset')) 0
+          in gf == gu && baFilled == fromList prefix <> baGen <> fromList suffix
+    ]
 
 rangeSpec ::
      forall a.
diff --git a/test/Spec/Stateful.hs b/test/Spec/Stateful.hs
index dbed18c4..167dcc16 100644
--- a/test/Spec/Stateful.hs
+++ b/test/Spec/Stateful.hs
@@ -155,15 +155,33 @@ frozenGenSpecFor fromStdGen toStdGen runStatefulGen =
       , testProperty "uniformWord64R/genWord64R" $
         forAll $ \w64 ->
           matchRandomGenSpec (uniformWord64R w64) (genWord64R w64) fromStdGen toStdGen runStatefulGen
-      , testProperty "uniformShortByteString/genShortByteString" $
+      , testProperty "uniformShortByteStringM/genShortByteString" $
         forAll $ \(NonNegative n') ->
           let n = n' `mod` 100000 -- Ensure it is not too big
           in matchRandomGenSpec
-               (uniformShortByteString n)
+               (uniformShortByteStringM n)
                (genShortByteString n)
                fromStdGen
                toStdGen
                runStatefulGen
+      , testProperty "uniformByteStringM/uniformByteString" $
+        forAll $ \(NonNegative n') ->
+          let n = n' `mod` 100000 -- Ensure it is not too big
+          in matchRandomGenSpec
+               (uniformByteStringM n)
+               (uniformByteString n)
+               fromStdGen
+               toStdGen
+               runStatefulGen
+      , testProperty "uniformByteArrayM/genByteArray" $
+        forAll $ \(NonNegative n', isPinned1, isPinned2) ->
+          let n = n' `mod` 100000 -- Ensure it is not too big
+          in matchRandomGenSpec
+               (uniformByteArrayM isPinned1 n)
+               (uniformByteArray isPinned2 n)
+               fromStdGen
+               toStdGen
+               runStatefulGen
       ]
     ]