diff --git a/Yesod/Helpers/Auth.hs b/Yesod/Helpers/Auth.hs
index d4f58290..6dff278e 100644
--- a/Yesod/Helpers/Auth.hs
+++ b/Yesod/Helpers/Auth.hs
@@ -40,6 +40,7 @@ import qualified Web.Authenticate.OpenId as OpenId
 import qualified Web.Authenticate.Facebook as Facebook
 
 import Yesod
+import Yesod.Mail (randomString)
 
 import Data.Maybe
 import Control.Monad
@@ -72,10 +73,10 @@ class Yesod master => YesodAuth master where
     -- | Generate a random alphanumeric string.
     --
     -- This is used for verify string in email authentication.
-    randomKey :: master -> GHandler (Auth master) master String
-    randomKey _ = liftIO $ do
+    randomKey :: master -> IO String
+    randomKey _ = do
         stdgen <- newStdGen
-        return $ take 10 $ randomRs ('A', 'Z') stdgen
+        return $ fst $ randomString 10 stdgen
 
 -- | Each authentication subsystem (OpenId, Rpxnow, Email, Facebook) has its
 -- own settings. If those settings are not present, then relevant handlers will
@@ -314,17 +315,18 @@ postEmailRegisterR :: YesodAuth master => GHandler (Auth master) master RepHtml
 postEmailRegisterR = do
     ae <- getAuthEmailSettings
     email <- runFormPost' $ emailInput "email"
-    y <- getYesod
     mecreds <- getEmailCreds ae email
     (lid, verKey) <-
         case mecreds of
             Just (EmailCreds lid _ _ (Just key)) -> return (lid, key)
             Just (EmailCreds lid _ _ Nothing) -> do
-                key <- randomKey y
+                y <- getYesod
+                key <- liftIO $ randomKey y
                 setVerifyKey ae lid key
                 return (lid, key)
             Nothing -> do
-                key <- randomKey y
+                y <- getYesod
+                key <- liftIO $ randomKey y
                 lid <- addUnverified ae email key
                 return (lid, key)
     render <- getUrlRender
diff --git a/Yesod/Mail.hs b/Yesod/Mail.hs
index 7411110c..256b43b5 100644
--- a/Yesod/Mail.hs
+++ b/Yesod/Mail.hs
@@ -9,6 +9,7 @@ module Yesod.Mail
     , sendmail
     , Disposition (..)
     , renderSendMail
+    , randomString
     ) where
 
 import qualified Data.ByteString.Lazy as L
@@ -23,21 +24,24 @@ import System.Exit
 import Codec.Binary.Base64 (encode)
 import Control.Monad ((<=<))
 
+randomString :: RandomGen d => Int -> d -> (String, d)
+randomString len =
+    first (map toChar) . sequence' (replicate len (randomR (0, 61)))
+  where
+    sequence' [] g = ([], g)
+    sequence' (f:fs) g =
+        let (f', g') = f g
+            (fs', g'') = sequence' fs g'
+         in (f' : fs', g'')
+    toChar i
+        | i < 26 = toEnum $ i + fromEnum 'A'
+        | i < 52 = toEnum $ i + fromEnum 'a' - 26
+        | otherwise = toEnum $ i + fromEnum '0' - 52
+
 newtype Boundary = Boundary { unBoundary :: String }
 instance Random Boundary where
     randomR = const random
-    random =
-        first (Boundary . map toChar) . sequence' (replicate 10 (randomR (0, 61)))
-      where
-        sequence' [] g = ([], g)
-        sequence' (f:fs) g =
-            let (f', g') = f g
-                (fs', g'') = sequence' fs g'
-             in (f' : fs', g'')
-        toChar i
-            | i < 26 = toEnum $ i + fromEnum 'A'
-            | i < 52 = toEnum $ i + fromEnum 'a' - 26
-            | otherwise = toEnum $ i + fromEnum '0' - 52
+    random = first Boundary . randomString 10
 
 data Mail = Mail
     { mailHeaders :: [(String, String)]
@@ -93,7 +97,7 @@ renderMail (Boundary b) (Mail headers plain parts) = toLazyByteString $ mconcat
         , fromByteString "\n"
         , case encoding of
             None -> writeList writeByteString $ L.toChunks content
-            Base64 -> fromString $ encode $ L.unpack content
+            Base64 -> writeList writeByte $ map (toEnum . fromEnum) $ encode $ L.unpack content
         ]
 
 renderMail' :: Mail -> IO L.ByteString