diff --git a/library/pkparse.c b/library/pkparse.c
index 9a55d6d..4ca359a 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -345,7 +345,7 @@
     /*
      * order INTEGER
      */
-    if( ( ret = asn1_get_mpi( &p, end, &grp->N ) ) )
+    if( ( ret = asn1_get_mpi( &p, end, &grp->N ) ) != 0 )
         return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret );
 
     grp->nbits = mpi_msb( &grp->N );