diff --git a/ndn-cpp/wire/base.h b/ndn-cpp/wire/base.h
new file mode 100644
index 0000000..8247d09
--- /dev/null
+++ b/ndn-cpp/wire/base.h
@@ -0,0 +1,33 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2013, Regents of the University of California
+ *                     Alexander Afanasyev
+ *
+ * BSD license, See the LICENSE file for more information
+ *
+ * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#ifndef NDN_WIRE_BASE_H
+#define NDN_WIRE_BASE_H
+
+#include "ndn-cpp/fields/signature-sha256-with-rsa.h"
+
+namespace ndn {
+namespace wire {
+
+/**
+ * @brief Class defining interface for double dispatch pattern (=visitor pattern)
+ *        to format variable fields in wire format
+ */
+class Base
+{
+public:
+  virtual void
+  appendSignature (std::ostream &os, const signature::Sha256WithRsa &signature, void *userData) = 0;
+};
+
+} // wire
+} // ndn
+
+#endif // NDN_WIRE_BASE_H