diff --git a/src/endorse-extension.hpp b/src/endorse-extension.hpp
new file mode 100644
index 0000000..844c55c
--- /dev/null
+++ b/src/endorse-extension.hpp
@@ -0,0 +1,78 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2013, Regents of the University of California
+ *
+ * BSD license, See the LICENSE file for more information
+ *
+ * Author: Qiuhan Ding <qiuhanding@cs.ucla.edu>
+ */
+
+#ifndef CHRONOCHAT_ENDORSE_EXTENSION_HPP
+#define CHRONOCHAT_ENDORSE_EXTENSION_HPP
+
+#include "common.hpp"
+#include "tlv.hpp"
+#include <ndn-cxx/util/concepts.hpp>
+#include <ndn-cxx/encoding/block.hpp>
+#include <ndn-cxx/encoding/encoding-buffer.hpp>
+#include <list>
+
+namespace chronochat {
+
+class EndorseExtension
+{
+
+public:
+
+  class Error : public std::runtime_error
+  {
+  public:
+    explicit
+    Error(const std::string& what)
+      : std::runtime_error(what)
+    {
+    }
+  };
+
+public:
+
+  EndorseExtension();
+
+  explicit
+  EndorseExtension(const Block& endorseWire);
+
+  const Block&
+  wireEncode() const;
+
+  void
+  wireDecode(const Block& endorseWire);
+
+  const std::list<std::string>&
+  getEntries() const;
+
+  void
+  addEntry(const std::string& entry);
+
+  void
+  removeEntry(const std::string& entry);
+
+private:
+  template<bool T>
+  size_t
+  wireEncode(ndn::EncodingImpl<T>& block) const;
+
+private:
+  mutable Block m_wire;
+  std::list<std::string> m_entries;
+};
+
+inline const std::list<std::string>&
+EndorseExtension::getEntries() const
+{
+  return m_entries;
+}
+
+
+} // namespace chronochat
+
+#endif //CHRONOCHAT_ENDORSE_EXTENSION_HPP