1 files changed, 29 insertions, 0 deletions
diff --git a/src/Network/WireGuard/Foreign/Key.hs b/src/Network/WireGuard/Foreign/Key.hs
new file mode 100644
index 0000000..2a0e7b8
--- /dev/null
+++ b/src/Network/WireGuard/Foreign/Key.hs
@@ -0,0 +1,29 @@
+module Network.WireGuard.Foreign.Key
+  ( Key
+  , fromByteString
+  , toByteString
+  ) where
+
+import qualified Data.ByteString                     as BS
+
+import           Foreign
+
+import           Network.WireGuard.Internal.Constant (keyLength)
+
+newtype Key = Key { fromKey :: [Word8] }
+
+instance Storable Key where
+    sizeOf _         = sizeOf (undefined :: Word8) * keyLength
+    alignment _      = alignment (undefined :: Word8)
+    peek ptr         = Key <$> peekArray keyLength (castPtr ptr)
+    poke ptr (Key k)
+        | length k == keyLength = pokeArray (castPtr ptr) k
+        | otherwise             = error "Key.poke: key length mismatch"
+
+fromByteString :: BS.ByteString -> Key
+fromByteString bs
+    | BS.length bs == keyLength = Key (BS.unpack bs)
+    | otherwise                 = error "Key.fromByteString: key length mismatch"
+
+toByteString :: Key -> BS.ByteString
+toByteString = BS.pack . fromKey