diff --git a/cryptoids/changes.md b/cryptoids/changes.md
index 4a074a0..dc1efca 100644
--- a/cryptoids/changes.md
+++ b/cryptoids/changes.md
@@ -1,3 +1,7 @@
+# 0.4.0.0
+    - Expose 'cipherBlockSize'
+    - Adjust 'Data.CryptoID.Poly' to allow for more dynamic padding
+
 # 0.3.0.0
     - Better exception type (does no longer leak private information)
     - 'Data.CryptoID.Poly' now supports padding the plaintext to a certain length before encryption
diff --git a/cryptoids/cryptoids.cabal b/cryptoids/cryptoids.cabal
index 2aa9240..e27c527 100644
--- a/cryptoids/cryptoids.cabal
+++ b/cryptoids/cryptoids.cabal
@@ -1,5 +1,5 @@
 name:                cryptoids
-version:             0.3.0.0
+version:             0.4.0.0
 synopsis:            Reversable and secure encoding of object ids as a bytestring
 license:             BSD3
 license-file:        LICENSE
diff --git a/cryptoids/src/Data/CryptoID/ByteString.hs b/cryptoids/src/Data/CryptoID/ByteString.hs
index eb5d31d..4b124c0 100644
--- a/cryptoids/src/Data/CryptoID/ByteString.hs
+++ b/cryptoids/src/Data/CryptoID/ByteString.hs
@@ -20,6 +20,7 @@ module Data.CryptoID.ByteString
   , decrypt
   , CryptoIDError(..)
   , CryptoCipher, CryptoHash
+  , cipherBlockSize
   ) where
 
 import Data.CryptoID
@@ -32,8 +33,6 @@ import Data.ByteString (ByteString)
 import qualified Data.ByteString as ByteString
 import qualified Data.ByteString.Char8 as ByteString.Char
 
-import qualified Data.ByteString.Lazy as Lazy (ByteString)
-
 import Data.List (sortOn)
 import Data.Ord (Down(..))
 
@@ -71,6 +70,10 @@ type CryptoCipher = Blowfish
 --
 -- Violation of this expectation causes runtime errors.
 type CryptoHash   = SHAKE128 64
+
+
+cipherBlockSize :: Int
+cipherBlockSize = blockSize (undefined :: CryptoCipher)
   
 
 -- | This newtype ensures only keys of the correct length can be created
@@ -209,4 +212,3 @@ decrypt (keyMaterial -> key) CryptoID{..} = do
   cipher <- cryptoFailable (cipherInit key :: CryptoFailable CryptoCipher)
   namespace <- namespace' (Proxy :: Proxy namespace)
   return $ cbcDecrypt cipher namespace ciphertext
-
diff --git a/cryptoids/src/Data/CryptoID/Poly.hs b/cryptoids/src/Data/CryptoID/Poly.hs
index 17769e3..65a4418 100644
--- a/cryptoids/src/Data/CryptoID/Poly.hs
+++ b/cryptoids/src/Data/CryptoID/Poly.hs
@@ -54,16 +54,16 @@ encrypt :: forall a m c namespace.
            ( KnownSymbol namespace
            , MonadThrow m
            , Binary a
-           ) => Maybe Int -- ^ Ensure the resulting ciphertext is of this size (needs to be a multiple of the block size of 'CryptoCipher' in bytes, otherwise an exception will be thrown at runtime)
+           ) => (ByteString -> m (Maybe Int)) -- ^ Ensure the resulting ciphertext is of the provided length (needs to be a multiple of the block size of 'CryptoCipher' in bytes, otherwise an exception will be thrown at runtime). The computation has access to the serialized plaintext
         -> (ByteString -> m c)
         -> CryptoIDKey
         -> a
         -> m (CryptoID namespace c)
-encrypt pLength encode' key plaintext = do
-  cID <- ByteString.encrypt key <=< pad . Lazy.ByteString.toStrict $ encode plaintext
+encrypt pLength' encode' key plaintext = do
+  cID <- ByteString.encrypt key <=< (\str -> pad str =<< pLength' str) . Lazy.ByteString.toStrict $ encode plaintext
   _ciphertext encode' cID
   where
-    pad str
+    pad str pLength
       | Just l <- pLength
       , l' <= l           = return $ str <> ByteString.replicate (l - l') 0
       | Just _ <- pLength = throwM $ CiphertextConversionFailed str
diff --git a/uuid-crypto/changes.md b/uuid-crypto/changes.md
index 7aaf13a..96f1360 100644
--- a/uuid-crypto/changes.md
+++ b/uuid-crypto/changes.md
@@ -1,3 +1,7 @@
+# 1.3.1.0
+    - Fix documentation mistake
+    - Bump @cryptoids@ to @0.4.0.*@
+
 # 1.3.0.1
     - Fix documentation typo
 
diff --git a/uuid-crypto/src/Data/UUID/Cryptographic.hs b/uuid-crypto/src/Data/UUID/Cryptographic.hs
index bad2a16..10a1c71 100644
--- a/uuid-crypto/src/Data/UUID/Cryptographic.hs
+++ b/uuid-crypto/src/Data/UUID/Cryptographic.hs
@@ -44,16 +44,13 @@ type CryptoUUID (namespace :: Symbol) = CryptoID namespace UUID
 -- | Encrypt an arbitrary serializable value
 --
 -- We only expect to fail if the given value is not serialized in such a fashion
--- that it fits within one 'CryptoCipher'-block.
---
--- Larger values could likely not be contained wholly within 128 bits (the size
--- of an 'UUID') in any case.
+-- that it fits within 128 bits (the length of an 'UUID').
 encrypt :: forall a m namespace.
            ( KnownSymbol namespace
            , Binary a
            , MonadThrow m
            ) => CryptoIDKey -> a -> m (CryptoUUID namespace)
-encrypt = Poly.encrypt (Just 16) $ \str -> maybe (throwM $ CiphertextConversionFailed str) return . fromByteString $ Lazy.ByteString.fromStrict str
+encrypt = Poly.encrypt (const . return $ Just 16) $ \str -> maybe (throwM $ CiphertextConversionFailed str) return . fromByteString $ Lazy.ByteString.fromStrict str
 
 
 -- | Decrypt an arbitrary serializable value
diff --git a/uuid-crypto/uuid-crypto.cabal b/uuid-crypto/uuid-crypto.cabal
index 6af244f..686474b 100644
--- a/uuid-crypto/uuid-crypto.cabal
+++ b/uuid-crypto/uuid-crypto.cabal
@@ -1,5 +1,5 @@
 name:                uuid-crypto
-version:             1.3.0.1
+version:             1.3.1.0
 synopsis:            Reversable and secure encoding of object ids as uuids
 license:             BSD3
 license-file:        LICENSE
@@ -28,7 +28,7 @@ library
   other-extensions:    ScopedTypeVariables
   build-depends:       base            >=4.9      && <4.11
                      , cryptoids-types ==0.0.0
-                     , cryptoids       ==0.3.0.*
+                     , cryptoids       ==0.4.0.*
                      , uuid            >=1.3.13   && <1.4
                      , binary          >=0.8.3.0  && <0.9
                      , bytestring      >=0.10.8.1 && <0.11