diff --git a/omnicodec.cabal b/omnicodec.cabal
--- a/omnicodec.cabal
+++ b/omnicodec.cabal
@@ -1,10 +1,10 @@
 name: omnicodec
-version: 0.3.1
+version: 0.4.0
 license: GPL
 license-file: COPYING
 author: Magnus Therning
 maintainer: magnus@therning.org
-copyright: Magnus Therning, 2007
+copyright: Magnus Therning, 2007-2010
 synopsis: data encoding and decoding command line utilities
 description: Two simple command line tools built on dataenc.
 build-type: Simple
@@ -14,11 +14,13 @@
 executable odec
   main-is: odec.hs
   hs-source-dirs: src
-  build-depends: base >= 4.0.0 && < 4.3, dataenc >= 0.13, directory, filepath, haskell98
+  build-depends: base >= 4.0.0 && < 4.3, dataenc >= 0.13, directory, filepath,
+      haskell98, bytestring
   ghc-options: -Wall
 
 executable oenc
   main-is: oenc.hs
   hs-source-dirs: src
-  build-depends: base >= 4.0.0 && < 4.3, dataenc >= 0.13, directory, filepath, haskell98
+  build-depends: base >= 4.0.0 && < 4.3, dataenc >= 0.13, directory, filepath,
+      haskell98, bytestring
   ghc-options: -Wall
diff --git a/src/odec.hs b/src/odec.hs
--- a/src/odec.hs
+++ b/src/odec.hs
@@ -21,7 +21,6 @@
     ) where
 
 import Codec.Binary.DataEncoding
-import Data.Char
 import Data.Maybe
 import Data.Version (showVersion)
 import Data.Word
@@ -29,18 +28,19 @@
 import System.Console.GetOpt
 import Control.Exception as CE
 import System.Directory
+import qualified Data.ByteString as BS
 
 import Paths_omnicodec (version)
 
 ver :: String
 ver = "omnicode decode (odec) " ++ (showVersion version)
-    ++ "\nCopyright 2007-2009 Magnus Therning <magnus@therning.org>"
+    ++ "\nCopyright 2007-2010 Magnus Therning <magnus@therning.org>"
 
 -- {{{1 Options
 data DecOptions = DecOptions {
     optDecode :: [String] -> [Maybe Word8],
     optRead :: IO String,
-    optWrite :: String -> IO (),
+    optWrite :: BS.ByteString -> IO (),
     optFn :: Maybe String  -- needed in case we need to clean up later on
     }
 
@@ -48,7 +48,7 @@
 defaultOptions = DecOptions {
     optDecode = decode' uu . unchop uu,
     optRead = getContents,
-    optWrite = putStr,
+    optWrite = BS.putStr,
     optFn = Nothing
     }
 
@@ -63,7 +63,7 @@
 
 -- {{{2 Processing command line
 setOptOutput :: FilePath -> DecOptions -> IO DecOptions
-setOptOutput fn opts = return opts { optWrite = writeFile fn, optFn = Just fn }
+setOptOutput fn opts = return opts { optWrite = BS.writeFile fn, optFn = Just fn }
 
 setOptCodec :: String -> DecOptions -> IO DecOptions
 setOptCodec codec opts = case codec of
@@ -89,9 +89,9 @@
 processFileName (fn:_) = return defaultOptions { optRead = readFile fn }
 processFileName _ = return defaultOptions
 
--- {{{1 _decode
-_decode :: DecOptions -> String -> IO String
-_decode opts = return .  map (chr . fromIntegral . fromMaybe (error "Illegal character")) . optDecode opts . lines
+-- {{{1 decode'
+_decode :: DecOptions -> String -> IO BS.ByteString
+_decode opts = return .  BS.pack. map (fromMaybe (error "Illegal character")) . optDecode opts . lines
 
 -- {{{1 main
 main :: IO ()
diff --git a/src/oenc.hs b/src/oenc.hs
--- a/src/oenc.hs
+++ b/src/oenc.hs
@@ -20,29 +20,29 @@
     where
 
 import Codec.Binary.DataEncoding
-import Data.Char
 import Data.Version (showVersion)
 import Data.Word
 import System
 import System.Console.GetOpt
+import qualified Data.ByteString as BS
 
 import Paths_omnicodec (version)
 
 ver :: String
 ver = "omnicode encode (oenc) " ++ (showVersion version)
-    ++ "\nCopyright 2007-2009 Magnus Therning <magnus@therning.org>"
+    ++ "\nCopyright 2007-2010 Magnus Therning <magnus@therning.org>"
 
 -- {{{1 Options
 data EncOptions = EncOptions {
     optEncode :: [Word8] -> [String],
-    optRead :: IO String,
+    optRead :: IO BS.ByteString,
     optWrite :: String -> IO ()
     }
 
 defaultOptions :: EncOptions
 defaultOptions = EncOptions {
     optEncode = chop uu 61 . encode uu,
-    optRead = getContents,
+    optRead = BS.getContents,
     optWrite = putStr
     }
 
@@ -79,12 +79,12 @@
 optShowHelp _ = putStr (usageInfo "Usage:" options) >> exitWith ExitSuccess
 
 processFileName :: [String] -> IO EncOptions
-processFileName (fn:_) = return defaultOptions { optRead = readFile fn }
+processFileName (fn:_) = return defaultOptions { optRead = BS.readFile fn }
 processFileName _ = return defaultOptions
 
 -- {{{1 encode
-encode' :: EncOptions -> String -> IO String
-encode' opts = return . unlines . optEncode opts . map (fromIntegral . ord)
+_encode :: EncOptions -> BS.ByteString -> IO String
+_encode opts = return . unlines . optEncode opts . BS.unpack
 
 -- {{{1 main
 main :: IO ()
@@ -92,4 +92,4 @@
     args <- getArgs
     let (actions, nonOpts, _) = getOpt RequireOrder options args
     opts <- foldl (>>=) (processFileName nonOpts) actions
-    optRead opts >>= encode' opts >>= optWrite opts
+    optRead opts >>= _encode opts >>= optWrite opts