diff --git a/src/security/transform/stream-sink.hpp b/src/security/transform/stream-sink.hpp
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+++ b/src/security/transform/stream-sink.hpp
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+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2016 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#ifndef NDN_CXX_SECURITY_TRANSFORM_STREAM_SINK_HPP
+#define NDN_CXX_SECURITY_TRANSFORM_STREAM_SINK_HPP
+
+#include "transform-base.hpp"
+#include <iostream>
+
+namespace ndn {
+namespace security {
+namespace transform {
+
+/**
+ * @brief A sink which directs output to an std::ostream.
+ */
+class StreamSink : public Sink
+{
+public:
+  /**
+   * @brief Create a stream sink which outputs to @p os
+   */
+  explicit
+  StreamSink(std::ostream& os);
+
+private:
+  /**
+   * @brief Write data into the stream
+   *
+   * @return number of bytes that have been written into the stream
+   */
+  virtual size_t
+  doWrite(const uint8_t* buf, size_t size) final;
+
+  /**
+   * @brief Finalize sink processing
+   */
+  virtual void
+  doEnd() final;
+
+private:
+  std::ostream& m_os;
+};
+
+unique_ptr<Sink>
+streamSink(std::ostream& os);
+
+} // namespace transform
+} // namespace security
+} // namespace ndn
+
+#endif // NDN_CXX_SECURITY_TRANSFORM_STREAM_SINK_HPP