diff --git a/clientsession.cabal b/clientsession.cabal
--- a/clientsession.cabal
+++ b/clientsession.cabal
@@ -1,5 +1,5 @@
 name:            clientsession
-version:         0.7.3.5
+version:         0.7.3.6
 license:         BSD3
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>, Felipe Lessa <felipe.lessa@gmail.com>
@@ -25,6 +25,7 @@
                    , bytestring          >= 0.9        && < 0.10
                    , cereal              >= 0.3        && < 0.4
                    , directory           >= 1          && < 1.2
+                   , tagged              >= 0.1
                    , crypto-api          >= 0.6.4      && < 0.9
                    , cryptocipher        >= 0.2.5
                    , skein               >= 0.1        && < 0.2
diff --git a/src/Web/ClientSession.hs b/src/Web/ClientSession.hs
--- a/src/Web/ClientSession.hs
+++ b/src/Web/ClientSession.hs
@@ -70,9 +70,13 @@
 -- from cereal
 import Data.Serialize (encode, decode)
 
+-- from tagged
+import Data.Tagged (Tagged, untag)
+
 -- from crypto-api
 import Crypto.Classes (buildKey)
-import Crypto.Random (reseed)
+import Crypto.Random (genSeedLength, reseed)
+import Crypto.Types (ByteLength)
 import qualified Crypto.Modes as Modes
 
 -- from cryptocipher
@@ -235,20 +239,18 @@
 -- | Reseed the CPRNG with new entropy from the system pool.
 aesReseed :: IO ()
 aesReseed = do
-  ent <- getEntropy 64 -- XXX: Is it possible for getEntropy
-                       --      to return less entropy than
-                       --      than we asked it?  I assume "no",
-                       --      but there's a check here just
-                       --      in case.
-  if S.length ent < 64
-    then I.atomicModifyIORef aesRef $
+  let len :: Tagged AESRNG ByteLength
+      len = genSeedLength
+  ent <- getEntropy (untag len)
+  I.atomicModifyIORef aesRef $
+       \(ASt rng _) ->
+           case reseed ent rng of
+             Right rng' -> (ASt rng' 0, ())
+             Left  _    -> (ASt rng  0, ())
              -- Use the old RNG, but force a reseed
              -- after another 'threshold' uses of it.
-             \(ASt rng _) -> (ASt rng 0, ())
-    else I.atomicModifyIORef aesRef $
-             \(ASt rng _) ->
-                 let Right rng' = reseed ent rng
-                 in (ASt rng' 0, ())
+             -- In theory, we will never reach this
+             -- branch, but if we do, we're safe.
 
 -- | 'IORef' that keeps the current state of the CPRNG.  Yep,
 -- global state.  Used in thread-safe was only, though.