refactor

1 files changed, 39 insertions, 2 deletions

diff --git a/Utility/Hash.hs b/Utility/Hash.hs
index 9881815bd..f960a134f 100644
--- a/Utility/Hash.hs
+++ b/Utility/Hash.hs
@@ -9,13 +9,16 @@ module Utility.Hash (
 	skein256,
 	skein512,
 	md5,
-	prop_hashes_stable
+	prop_hashes_stable,
+	Mac(..),
+	calcMac,
+	prop_mac_stable,
 ) where
 
 import qualified Data.ByteString.Lazy as L
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as T
-
+import qualified Data.ByteString as S
 import Crypto.Hash
 
 sha1 :: L.ByteString -> Digest SHA1
@@ -60,3 +63,37 @@ prop_hashes_stable = all (\(hasher, result) -> hasher foo == result)
 	]
   where
 	foo = L.fromChunks [T.encodeUtf8 $ T.pack "foo"]
+
+{- File names are (client-side) MAC'ed on special remotes.
+ - The chosen MAC algorithm needs to be same for all files stored on the
+ - remote.
+ -}
+data Mac = HmacSha1 | HmacSha224 | HmacSha256 | HmacSha384 | HmacSha512
+	deriving (Eq)
+
+calcMac
+	:: Mac          -- ^ MAC
+	-> S.ByteString -- ^ secret key
+	-> S.ByteString -- ^ message
+	-> String       -- ^ MAC'ed message, in hexadecimal
+calcMac mac = case mac of
+	HmacSha1   -> use SHA1
+	HmacSha224 -> use SHA224
+	HmacSha256 -> use SHA256
+	HmacSha384 -> use SHA384
+	HmacSha512 -> use SHA512
+  where
+	use alg k m = show (hmacGetDigest (hmacAlg alg k m))
+
+-- Check that all the MACs continue to produce the same.
+prop_mac_stable :: Bool
+prop_mac_stable = all (\(mac, result) -> calcMac mac key msg == result)
+	[ (HmacSha1, "46b4ec586117154dacd49d664e5d63fdc88efb51")
+	, (HmacSha224, "4c1f774863acb63b7f6e9daa9b5c543fa0d5eccf61e3ffc3698eacdd")
+	, (HmacSha256, "f9320baf0249169e73850cd6156ded0106e2bb6ad8cab01b7bbbebe6d1065317")
+	, (HmacSha384, "3d10d391bee2364df2c55cf605759373e1b5a4ca9355d8f3fe42970471eca2e422a79271a0e857a69923839015877fc6")
+	, (HmacSha512, "114682914c5d017dfe59fdc804118b56a3a652a0b8870759cf9e792ed7426b08197076bf7d01640b1b0684df79e4b67e37485669e8ce98dbab60445f0db94fce")
+	]
+  where
+	key = T.encodeUtf8 $ T.pack "foo"
+	msg = T.encodeUtf8 $ T.pack "bar"