diff --git a/src/Data/Word/Crc32.hs b/src/Data/Word/Crc32.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Word/Crc32.hs
@@ -0,0 +1,51 @@
+{-# LANGUAGE ImportQualifiedPost #-}
+{-# LANGUAGE BlockArguments, OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE RequiredTypeArguments #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# OPTIONS_GHC -Wall -fno-warn-tabs #-}
+
+module Data.Word.Crc32 (
+
+	C, fromWord, toWord, step, initial, complement
+
+	) where
+
+import Control.Arrow
+import Data.Bits hiding (complement)
+import Data.Bits qualified as Bits
+import Data.Bits.ToolsYj
+import Data.Array
+import Data.Bool
+import Data.Word
+
+newtype C = C { unC :: Word32 } deriving (Show, Eq)
+
+fromWord :: Word32 -> C
+fromWord = C
+
+toWord :: C -> Word32
+toWord = unC
+
+crc1 :: Word32 -> Word32
+crc1 = uncurry (bool id (`xor` 0xedb88320)) . popBit
+
+crc8 :: Word8 -> Word32
+crc8 n = iterate crc1 (fromIntegral n) !! 8
+
+table :: Array Word8 Word32
+table = listArray (0, 255) $ map crc8 [0 .. 255]
+
+popByte :: (Integral a, Bits a) => a -> (Word8, a)
+popByte n = (fromIntegral n, n `shiftR` 8)
+
+step :: C -> Word8 -> C
+step (C n) b = C . uncurry xor . (first $ (table !) . (`xor` b)) $ popByte n
+
+initial :: C
+initial = C 0xffffffff
+
+complement :: C -> C
+complement = C . Bits.complement . unC
diff --git a/tools-yj.cabal b/tools-yj.cabal
--- a/tools-yj.cabal
+++ b/tools-yj.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           tools-yj
-version:        0.1.0.34
+version:        0.1.0.35
 synopsis:       Tribial tools
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/tools-yj#readme>
 category:       Tools
@@ -43,6 +43,7 @@
       Data.Sequences.ToolsYj
       Data.Text.ToolsYj
       Data.Tuple.ToolsYj
+      Data.Word.Crc32
       Text.Show.ToolsYj
   other-modules:
       Paths_tools_yj
@@ -52,7 +53,8 @@
       src
   ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints
   build-depends:
-      base >=4.7 && <5
+      array <1
+    , base >=4.7 && <5
     , bytestring <1
     , containers <1
     , data-default <1
@@ -72,7 +74,8 @@
       test
   ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N
   build-depends:
-      base >=4.7 && <5
+      array <1
+    , base >=4.7 && <5
     , bytestring <1
     , containers <1
     , data-default <1