git-annex/Types/Crypto.hs
2015-04-19 10:54:12 -04:00

89 lines
2.6 KiB
Haskell

{- git-annex crypto types
-
- Copyright 2011-2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Types.Crypto (
Cipher(..),
StorableCipher(..),
EncryptedCipherVariant(..),
KeyIds(..),
Mac(..),
readMac,
showMac,
defaultMac,
calcMac,
) where
import qualified Data.Text as T
import qualified Data.Text.Encoding as T
import Data.Digest.Pure.SHA
import qualified Data.ByteString as B
import Crypto.Hash
import Utility.Gpg (KeyIds(..))
-- XXX ideally, this would be a locked memory region
data Cipher = Cipher String | MacOnlyCipher String
data StorableCipher = EncryptedCipher String EncryptedCipherVariant KeyIds
| SharedCipher String
deriving (Ord, Eq)
data EncryptedCipherVariant = Hybrid | PubKey
deriving (Ord, Eq)
{- 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)
defaultMac :: Mac
defaultMac = HmacSha1
-- MAC algorithms are shown as follows in the file names.
showMac :: Mac -> String
showMac HmacSha1 = "HMACSHA1"
showMac HmacSha224 = "HMACSHA224"
showMac HmacSha256 = "HMACSHA256"
showMac HmacSha384 = "HMACSHA384"
showMac HmacSha512 = "HMACSHA512"
-- Read the MAC algorithm from the remote config.
readMac :: String -> Maybe Mac
readMac "HMACSHA1" = Just HmacSha1
readMac "HMACSHA224" = Just HmacSha224
readMac "HMACSHA256" = Just HmacSha256
readMac "HMACSHA384" = Just HmacSha384
readMac "HMACSHA512" = Just HmacSha512
readMac _ = Nothing
calcMac
:: Mac -- ^ MAC
-> B.ByteString -- ^ secret key
-> B.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"