diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,9 @@
 # Changelog
 
+- 0.3.2 (2026-05-16)
+  * Bumps the poly1305 dependency to a version that returns its MAC in a
+    custom type having a constant-time Eq instance.
+
 - 0.3.1 (2025-12-28)
   * Tests with GHC 9.10.3.
 
diff --git a/lib/Crypto/AEAD/ChaCha20Poly1305.hs b/lib/Crypto/AEAD/ChaCha20Poly1305.hs
--- a/lib/Crypto/AEAD/ChaCha20Poly1305.hs
+++ b/lib/Crypto/AEAD/ChaCha20Poly1305.hs
@@ -123,7 +123,7 @@
               md3 = md2 <> unroll8 (fi (BS.length cip))
           case Poly1305.mac otk md3 of
             Nothing -> Left InvalidKey
-            Just tag -> pure (cip, tag)
+            Just (Poly1305.MAC tag) -> pure (cip, tag)
 
 -- | Decrypt an authenticated ciphertext, given a message authentication
 --   code and some additional authenticated data, via a 256-bit key and
@@ -151,7 +151,7 @@
           md3 = md2 <> unroll8 (fi (BS.length cip))
       case Poly1305.mac otk md3 of
         Nothing -> Left InvalidKey
-        Just tag
+        Just (Poly1305.MAC tag)
           | ct_eq mac tag -> case ChaCha20.cipher key 1 nonce cip of
               Left ChaCha20.InvalidKey -> Left InvalidKey
               Left ChaCha20.InvalidNonce -> Left InvalidNonce
diff --git a/ppad-aead.cabal b/ppad-aead.cabal
--- a/ppad-aead.cabal
+++ b/ppad-aead.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               ppad-aead
-version:            0.3.1
+version:            0.3.2
 synopsis:           A pure AEAD-ChaCha20-Poly1305 construction
 license:            MIT
 license-file:       LICENSE
@@ -15,6 +15,11 @@
   (AEAD) implementation supporting ChaCha20-Poly1305, per
   [RFC8439](https://datatracker.ietf.org/doc/html/rfc8439).
 
+flag llvm
+  description: Use GHC's LLVM backend.
+  default:     False
+  manual:      True
+
 source-repository head
   type:     git
   location: git.ppad.tech/aead.git
@@ -24,6 +29,8 @@
   hs-source-dirs:   lib
   ghc-options:
       -Wall
+  if flag(llvm)
+    ghc-options: -fllvm -O2
   exposed-modules:
       Crypto.AEAD.ChaCha20Poly1305
   build-depends: