diff --git a/Annex.hs b/Annex.hs
index dd3362b29d..f8cfd0ec92 100644
--- a/Annex.hs
+++ b/Annex.hs
@@ -25,7 +25,7 @@ import Data.Maybe
 
 import qualified GitRepo as Git
 import qualified GitQueue
-import qualified BackendTypes
+import qualified BackendClass
 import Utility
 
 -- git-annex's monad
@@ -34,8 +34,8 @@ type Annex = StateT AnnexState IO
 -- internal state storage
 data AnnexState = AnnexState
 	{ repo :: Git.Repo
-	, backends :: [BackendTypes.Backend Annex]
-	, supportedBackends :: [BackendTypes.Backend Annex]
+	, backends :: [BackendClass.Backend Annex]
+	, supportedBackends :: [BackendClass.Backend Annex]
 	, repoqueue :: GitQueue.Queue
 	, quiet :: Bool
 	, force :: Bool
@@ -47,7 +47,7 @@ data AnnexState = AnnexState
 	, remotesread :: Bool
 	} deriving (Show)
 
-newState :: Git.Repo -> [BackendTypes.Backend Annex] -> AnnexState
+newState :: Git.Repo -> [BackendClass.Backend Annex] -> AnnexState
 newState gitrepo allbackends = AnnexState
 	{ repo = gitrepo
 	, backends = []
@@ -64,7 +64,7 @@ newState gitrepo allbackends = AnnexState
 	}
 
 {- Create and returns an Annex state object for the specified git repo. -}
-new :: Git.Repo -> [BackendTypes.Backend Annex] -> IO AnnexState
+new :: Git.Repo -> [BackendClass.Backend Annex] -> IO AnnexState
 new gitrepo allbackends = do
 	gitrepo' <- liftIO $ Git.configRead gitrepo
 	return $ newState gitrepo' allbackends
diff --git a/Backend.hs b/Backend.hs
index 94755e8d6b..e1f8f388b9 100644
--- a/Backend.hs
+++ b/Backend.hs
@@ -40,7 +40,7 @@ import qualified GitRepo as Git
 import qualified Annex
 import Types
 import Key
-import qualified BackendTypes as B
+import qualified BackendClass as B
 import Messages
 
 {- List of backends in the order to try them when storing a new key. -}
diff --git a/Backend/File.hs b/Backend/File.hs
index d76cd29391..a5e2431998 100644
--- a/Backend/File.hs
+++ b/Backend/File.hs
@@ -18,7 +18,7 @@ import Control.Monad.State
 import System.Directory
 import Data.List
 
-import BackendTypes
+import BackendClass
 import LocationLog
 import Locations
 import qualified Remotes
diff --git a/Backend/SHA.hs b/Backend/SHA.hs
index 3cdc3bf808..0563851076 100644
--- a/Backend/SHA.hs
+++ b/Backend/SHA.hs
@@ -16,7 +16,7 @@ import Data.Maybe
 import System.Posix.Files
 
 import qualified Backend.File
-import BackendTypes
+import BackendClass
 import Messages
 import qualified Annex
 import Locations
diff --git a/Backend/URL.hs b/Backend/URL.hs
index 29dc8fefa7..b40ff39599 100644
--- a/Backend/URL.hs
+++ b/Backend/URL.hs
@@ -11,7 +11,7 @@ import Control.Monad.State (liftIO)
 import Data.String.Utils
 
 import Types
-import BackendTypes
+import BackendClass
 import Utility
 import Messages
 
diff --git a/Backend/WORM.hs b/Backend/WORM.hs
index 324aee76be..a011995da3 100644
--- a/Backend/WORM.hs
+++ b/Backend/WORM.hs
@@ -14,7 +14,7 @@ import System.Directory
 import Data.Maybe
 
 import qualified Backend.File
-import BackendTypes
+import BackendClass
 import Locations
 import qualified Annex
 import Content
diff --git a/BackendTypes.hs b/BackendClass.hs
similarity index 97%
rename from BackendTypes.hs
rename to BackendClass.hs
index 48b208a9b4..909ae8f96e 100644
--- a/BackendTypes.hs
+++ b/BackendClass.hs
@@ -7,7 +7,7 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
-module BackendTypes where
+module BackendClass where
 
 import Key
 
diff --git a/Command.hs b/Command.hs
index 38c63bd77e..18b4a167aa 100644
--- a/Command.hs
+++ b/Command.hs
@@ -17,7 +17,7 @@ import Data.List
 
 import Types
 import qualified Backend
-import qualified BackendTypes
+import qualified BackendClass
 import Messages
 import qualified Annex
 import qualified GitRepo as Git
@@ -237,7 +237,7 @@ cmdlineKey  = do
 	backends <- Backend.list
 	return $ stubKey {
 		keyName = kname k,
-		keyBackendName = BackendTypes.name $ head backends
+		keyBackendName = BackendClass.name $ head backends
 	}
 	where
 		kname Nothing = badkey
diff --git a/Command/InAnnex.hs b/Command/InAnnex.hs
index 4a4102754a..a2beda4a59 100644
--- a/Command/InAnnex.hs
+++ b/Command/InAnnex.hs
@@ -13,7 +13,7 @@ import System.Exit
 import Command
 import Content
 import qualified Backend
-import qualified BackendTypes
+import qualified BackendClass
 import Key
 
 command :: [Command]
@@ -28,7 +28,7 @@ start keyname = do
 	backends <- Backend.list
 	let key = stubKey {
 		keyName = keyname,
-		keyBackendName = BackendTypes.name (head backends)
+		keyBackendName = BackendClass.name (head backends)
 	}
 	error "BROKEN. fixme!"
 	present <- inAnnex key
diff --git a/Key.hs b/Key.hs
index 3385148707..f52aea31b7 100644
--- a/Key.hs
+++ b/Key.hs
@@ -76,11 +76,10 @@ instance Arbitrary Key where
 	arbitrary = do
 		n <- arbitrary
 		b <- elements ['A'..'Z']
-		s <- arbitrary
 		return $ Key {
 			keyName = n,
 			keyBackendName = [b],
-			keySize = s,
+			keySize = Nothing,
 			keyMtime = Nothing
 		}
 
diff --git a/Types.hs b/Types.hs
index f48d4079be..503e27d312 100644
--- a/Types.hs
+++ b/Types.hs
@@ -11,6 +11,6 @@ module Types (
 	Key
 ) where
 
-import BackendTypes
+import BackendClass
 import Annex
 import Key
diff --git a/test.hs b/test.hs
index bc849dadc5..2bc0c37a37 100644
--- a/test.hs
+++ b/test.hs
@@ -29,7 +29,7 @@ import qualified Backend
 import qualified GitRepo as Git
 import qualified Locations
 import qualified Utility
-import qualified BackendTypes
+import qualified BackendClass
 import qualified Types
 import qualified GitAnnex
 import qualified LocationLog
@@ -120,8 +120,8 @@ test_add = "git-annex add" ~: TestList [basic, sha1dup]
 test_setkey :: Test
 test_setkey = "git-annex setkey/fromkey" ~: TestCase $ inmainrepo $ do
 	writeFile tmp $ content sha1annexedfile
-	r <- annexeval $ BackendTypes.getKey backendSHA1 tmp
-	let sha1 = BackendTypes.keyName $ fromJust r
+	r <- annexeval $ BackendClass.getKey backendSHA1 tmp
+	let sha1 = Key.keyName $ fromJust r
 	git_annex "setkey" ["-q", "--backend", "SHA1", "--key", sha1, tmp] @? "setkey failed"
 	git_annex "fromkey" ["-q", "--backend", "SHA1", "--key", sha1, sha1annexedfile] @? "fromkey failed"
 	Utility.boolSystem "git" [Utility.Params "commit -q -a -m commit"] @? "git commit failed"
@@ -439,7 +439,7 @@ test_unused = "git-annex unused/dropunused" ~: intmpclonerepo $ do
 	checkunused [annexedfilekey, sha1annexedfilekey]
 
 	-- good opportunity to test dropkey also
-	git_annex "dropkey" ["-q", "--force", BackendTypes.keyName annexedfilekey]
+	git_annex "dropkey" ["-q", "--force", Key.keyName annexedfilekey]
 		@? "dropkey failed"
 	checkunused [sha1annexedfilekey]