diff --git a/simon.h b/simon.h
index 7313dbdd..43d06355 100644
--- a/simon.h
+++ b/simon.h
@@ -53,7 +53,7 @@ template <class W>
 struct SIMON_Base
 {
     virtual ~SIMON_Base() {}
-    SIMON_Base() : m_kwords(0) {}
+SIMON_Base() : m_kwords(0), m_rounds(0) {}
 
     typedef SecBlock<W, AllocatorWithCleanup<W, true> > AlignedSecBlock;
     mutable AlignedSecBlock m_wspace;  // workspace