diff --git a/Certificate.hs b/Certificate.hs
--- a/Certificate.hs
+++ b/Certificate.hs
@@ -82,12 +82,12 @@
 			printf "  modulus: %x\n" (RSA.public_n pubkey)
 			printf "  e      : %x\n" (RSA.public_e pubkey)
 		X509.PubKeyDSA pubkey -> do
-			let (p,q,g) = DSA.public_params pubkey
+			let params = DSA.public_params pubkey
 			putStrLn "public key DSA:"
 			printf "  pub    : %x\n" (DSA.public_y pubkey)
-			printf "  p      : %d\n" p
-			printf "  q      : %x\n" q
-			printf "  g      : %x\n" g
+			printf "  p      : %d\n" (DSA.params_p params)
+			printf "  q      : %x\n" (DSA.params_q params)
+			printf "  g      : %x\n" (DSA.params_g params)
 		X509.PubKeyUnknown oid ws -> do
 			printf "public key unknown: %s\n" (show oid)
 			printf "  raw bytes: %s\n" (show ws)
@@ -122,11 +122,11 @@
 showDSAKey (pubkey,privkey) = unlines
 	[ "priv     " ++ (printf "%x" $ DSA.private_x privkey)
 	, "pub:     " ++ (printf "%x" $ DSA.public_y pubkey)
-	, "p:       " ++ (printf "%x" p)
-	, "q:       " ++ (printf "%x" g)
-	, "g:       " ++ (printf "%x" q)
+	, "p:       " ++ (printf "%x" $ DSA.params_p params)
+	, "q:       " ++ (printf "%x" $ DSA.params_q params)
+	, "g:       " ++ (printf "%x" $ DSA.params_g params)
 	]
-    where (p,q,g) = DSA.private_params privkey
+    where params = DSA.private_params privkey
 
 showASN1 :: Int -> [ASN1] -> IO ()
 showASN1 at = prettyPrint at where
diff --git a/Data/Certificate/KeyDSA.hs b/Data/Certificate/KeyDSA.hs
--- a/Data/Certificate/KeyDSA.hs
+++ b/Data/Certificate/KeyDSA.hs
@@ -27,7 +27,7 @@
     where
         privkey = DSA.PrivateKey { DSA.private_params = params, DSA.private_x = priv }
         pubkey  = DSA.PublicKey { DSA.public_params = params, DSA.public_y = pub }
-        params  = (p,g,q)
+        params  = DSA.Params { DSA.params_p = p, DSA.params_g = g, DSA.params_q = q }
 
 parsePrivate (Start Sequence : IntVal n : _)
         | n == 0    = Left "DSA key format: not recognized"
@@ -42,11 +42,11 @@
         where pkseq =
                 [ Start Sequence
                 , IntVal 0
-                , IntVal p
-                , IntVal q
-                , IntVal g
+                , IntVal $ DSA.params_p params
+                , IntVal $ DSA.params_q params
+                , IntVal $ DSA.params_g params
                 , IntVal $ DSA.public_y pubkey
                 , IntVal $ DSA.private_x privkey
                 , End Sequence
                 ]
-              (p,g,q) = DSA.private_params privkey
+              params = DSA.private_params privkey
diff --git a/Data/Certificate/X509/Cert.hs b/Data/Certificate/X509/Cert.hs
--- a/Data/Certificate/X509/Cert.hs
+++ b/Data/Certificate/X509/Cert.hs
@@ -256,7 +256,10 @@
           toKey PubKeyALG_DSA [Start Sequence,IntVal p,IntVal q,IntVal g,End Sequence] bits = do
                 case decodeASN1 BER bits of
                      Right [IntVal dsapub] -> return $ PubKeyDSA $ DSA.PublicKey
-                                                                     { DSA.public_params = (p, q, g)
+                                                                     { DSA.public_params = DSA.Params
+                                                                             { DSA.params_p = p
+                                                                             , DSA.params_q = q
+                                                                             , DSA.params_g = g }
                                                                      , DSA.public_y = dsapub }
                      _                     -> return $ PubKeyUnknown (pubkeyalgOID PubKeyALG_DSA) $ L.unpack bits
           toKey (PubKeyALG_Unknown oid) _ bits = return $ PubKeyUnknown oid $ L.unpack bits
@@ -340,8 +343,10 @@
         asn1Container Sequence (asn1Container Sequence ([pkalg] ++ dsaseq) ++ [BitString $ toBitArray bits 0])
         where
                 pkalg   = OID $ pubkeyalgOID $ pubkeyToAlg k
-                dsaseq  = asn1Container Sequence [IntVal p,IntVal q,IntVal g]
-                (p,q,g) = DSA.public_params pubkey
+                dsaseq  = asn1Container Sequence [IntVal (DSA.params_p params)
+                                                 ,IntVal (DSA.params_q params)
+                                                 ,IntVal (DSA.params_g params)]
+                params  = DSA.public_params pubkey
                 bits    = encodeASN1 DER [IntVal $ DSA.public_y pubkey]
 
 encodePK k@(PubKeyUnknown _ l) =
diff --git a/certificate.cabal b/certificate.cabal
--- a/certificate.cabal
+++ b/certificate.cabal
@@ -1,5 +1,5 @@
 Name:                certificate
-Version:             1.3.6
+Version:             1.3.7
 Description:
     Certificates and Key reader/writer
     .
@@ -31,7 +31,7 @@
                    , mtl
                    , pem >= 0.1 && < 0.2
                    , asn1-data >= 0.7.1 && < 0.8.0
-                   , crypto-pubkey-types >= 0.2 && < 0.3
+                   , crypto-pubkey-types >= 0.3 && < 0.4
                    , cryptohash
                    , containers
                    , directory