diff --git a/cacophony.cabal b/cacophony.cabal
--- a/cacophony.cabal
+++ b/cacophony.cabal
@@ -1,5 +1,5 @@
 name:          cacophony
-version:       0.9.0
+version:       0.9.1
 synopsis:      A library implementing the Noise protocol.
 license:       PublicDomain
 license-file:  LICENSE
@@ -10,7 +10,7 @@
 category:      Cryptography
 build-type:    Simple
 cabal-version: >=1.10
-tested-with:   GHC == 7.10.3, GHC == 8.0.2
+tested-with:   GHC == 7.10.3, GHC == 8.0.1
 description:
   This library implements the <https://github.com/trevp/noise/blob/master/noise.md Noise>
   protocol.
@@ -57,7 +57,6 @@
     base       >=4.8 && <5,
     bytestring,
     cryptonite >=0.16,
-    deepseq,
     exceptions >=0.8.3,
     free,
     lens,
@@ -131,6 +130,9 @@
 
   ghc-options:      -threaded -O2 -rtsopts -with-rtsopts=-N -Wall -fwarn-tabs
 
+  if flag(llvm)
+    ghc-options: -fllvm
+
 executable echo-client
   default-language: Haskell2010
   hs-source-dirs:   examples/echo-client
@@ -159,6 +161,9 @@
 
   ghc-options:      -threaded -O2 -rtsopts -with-rtsopts=-N -Wall -fwarn-tabs
 
+  if flag(llvm)
+    ghc-options: -fllvm
+
 --------------------------------------------------------------------------------
 -- TESTS
 
@@ -176,6 +181,9 @@
       base  >=4.8 && <5,
       hlint
 
+  if flag(llvm)
+    ghc-options: -fllvm
+
 test-suite vectors
   type:             exitcode-stdio-1.0
   main-is:          vectors.hs
@@ -207,6 +215,9 @@
     VectorFile,
     Verify
 
+  if flag(llvm)
+    ghc-options: -fllvm
+
 --------------------------------------------------------------------------------
 -- BENCHMARKS
 
@@ -231,3 +242,6 @@
   other-modules:
     Handshakes
     Types
+
+  if flag(llvm)
+    ghc-options: -fllvm
diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,13 @@
+# 0.9.1
+
+* Enabled llvm flag support on executables
+
+* Removed deepseq library dependency
+
+* Disallowed reserved nonce (2^64 - 1)
+
+* Fixed problem with CipherState count not incrementing
+
 # 0.9.0
 
 * Removed secondary key support (rev 31)
diff --git a/src/Crypto/Noise.hs b/src/Crypto/Noise.hs
--- a/src/Crypto/Noise.hs
+++ b/src/Crypto/Noise.hs
@@ -57,7 +57,7 @@
 --   handshake. Please see section 8.4 of the protocol document for details.
 --
 --   To prevent catastrophic key re-use, this function may only be used to
---   secure 2^64 post-handshake messages.
+--   secure 2^64 - 1 post-handshake messages.
 writeMessage :: (MonadThrow m, Cipher c, Hash h)
              => NoiseState c d h
              -> ScrubbedBytes
@@ -76,7 +76,7 @@
 --   is complete, if decryption fails a 'DecryptionError' is returned.
 --
 --   To prevent catastrophic key re-use, this function may only be used to
---   receive 2^64 post-handshake messages.
+--   receive 2^64 - 1 post-handshake messages.
 readMessage :: (MonadThrow m, Cipher c, Hash h)
             => NoiseState c d h
             -> ByteString
diff --git a/src/Crypto/Noise/Internal/CipherState.hs b/src/Crypto/Noise/Internal/CipherState.hs
--- a/src/Crypto/Noise/Internal/CipherState.hs
+++ b/src/Crypto/Noise/Internal/CipherState.hs
@@ -33,8 +33,9 @@
   | otherwise = throwM $ MessageLimitReached "encryptAndIncrement"
   where
     ct       = cipherEncrypt (cs ^. csk) (cs ^. csn) ad plaintext
-    newState = cs & csn %~ cipherIncNonce
-    allow    = cs ^. csCount < 2 ^ (64 :: Integer)
+    newState = cs & csn     %~ cipherIncNonce
+                  & csCount %~ (+1)
+    allow    = cs ^. csCount < 2 ^ (64 :: Integer) - 1
 
 decryptAndIncrement :: (MonadThrow m, Cipher c)
                     => AssocData
@@ -49,5 +50,6 @@
   | otherwise = throwM $ MessageLimitReached "decryptAndIncrement"
   where
     pt       = cipherDecrypt (cs ^. csk) (cs ^. csn) ad ct
-    newState = maybe cs (const (cs & csn %~ cipherIncNonce)) pt
-    allow    = cs ^. csCount < 2 ^ (64 :: Integer)
+    newState = cs & csn     %~ cipherIncNonce
+                  & csCount %~ (+1)
+    allow    = cs ^. csCount < 2 ^ (64 :: Integer) - 1