diff --git a/Crypto/Error/Types.hs b/Crypto/Error/Types.hs
index 368f5ef..225660c 100644
--- a/Crypto/Error/Types.hs
+++ b/Crypto/Error/Types.hs
@@ -29,6 +29,10 @@ data CryptoError =
       CryptoError_KeySizeInvalid
     | CryptoError_IvSizeInvalid
     | CryptoError_AEADModeNotSupported
+    -- public key cryptography error
+    | CryptoError_SecretKeySizeInvalid
+    | CryptoError_SecretKeyStructureInvalid
+    | CryptoError_PublicKeySizeInvalid
     deriving (Show,Eq,Enum,Data,Typeable)
 
 instance E.Exception CryptoError
diff --git a/cryptonite.cabal b/cryptonite.cabal
index 94bb9d4..c5b69b3 100644
--- a/cryptonite.cabal
+++ b/cryptonite.cabal
@@ -129,7 +129,6 @@ Library
                      Crypto.Internal.CompatPrim
                      Crypto.Internal.Bytes
                      Crypto.Internal.Endian
-                     Crypto.Internal.Hex
                      Crypto.Internal.Imports
                      Crypto.Internal.Memory
                      Crypto.Internal.Words