diff --git a/c_src/sign.c b/c_src/sign.c
index 292e31c..fb06203 100644
--- a/c_src/sign.c
+++ b/c_src/sign.c
@@ -468,6 +468,10 @@ enacl_crypto_sign_verify_detached(ErlNifEnv *env, int argc,
     return enif_make_badarg(env);
   }
 
+  if (sig.size != crypto_sign_BYTES) {
+    return enif_make_badarg(env);
+  }
+
   if (pk.size != crypto_sign_PUBLICKEYBYTES) {
     return enif_make_badarg(env);
   }
diff --git a/eqc_test/enacl_eqc.erl b/eqc_test/enacl_eqc.erl
index 38464b4..6093a5b 100644
--- a/eqc_test/enacl_eqc.erl
+++ b/eqc_test/enacl_eqc.erl
@@ -419,7 +419,7 @@ signed_message(M) ->
     ?FAULT(signed_message_bad(), signed_message_good(M)).
 
 signed_message_d(M) ->
-    ?FAULT(signed_message_bad(), signed_message_good(M)).
+    ?FAULT(signed_message_bad_d(), signed_message_good_d(M)).
 
 signed_message_valid({valid, _}, _) -> true;
 signed_message_valid({invalid, _}, _) -> true;