1 files changed, 6 insertions, 2 deletions
diff --git a/Crypto.hs b/Crypto.hs
index 2fe27e0..af3ad17 100644
--- a/Crypto.hs
+++ b/Crypto.hs
@@ -16,6 +16,7 @@ import Crypto.Error
 import Crypto.Random.Entropy
 import Data.ByteArray (convert)
 import qualified Data.ByteString as B
+import qualified Data.Semigroup as Sem
 
 dummySignature :: Signature
 dummySignature = OtherSignature (Val mempty)
@@ -78,10 +79,13 @@ mkSigVerifier (PublicKey (Val pk)) =
 		CryptoPassed pk' -> SigVerifier 1 (Ed25519.verify pk')
 		CryptoFailed _ -> mempty
 
+instance Sem.Semigroup SigVerifier where
+	SigVerifier na a <> SigVerifier nb b =
+		SigVerifier (na+nb) $ \d s -> b d s || a d s
+
 instance Monoid SigVerifier where
 	mempty = SigVerifier 0 $ \_b _s -> False
-	mappend (SigVerifier na a) (SigVerifier nb b) =
-		SigVerifier (na+nb) $ \d s -> b d s || a d s
+	mappend = (Sem.<>)
 
 data MySessionKey = MySessionKey Ed25519.SecretKey Ed25519.PublicKey