diff --git a/src/consumer-db.hpp b/src/consumer-db.hpp
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+++ b/src/consumer-db.hpp
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+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2015,  Regents of the University of California
+ *
+ * This file is part of ndn-group-encrypt (Group-based Encryption Protocol for NDN).
+ * See AUTHORS.md for complete list of ndn-group-encrypt authors and contributors.
+ *
+ * ndn-group-encrypt is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-group-encrypt 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * ndn-group-encrypt, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @author Zhiyi Zhang <dreamerbarrychang@gmail.com>
+ */
+
+#ifndef NDN_GEP_CONSUMER_DB_HPP
+#define NDN_GEP_CONSUMER_DB_HPP
+
+#include "common.hpp"
+
+namespace ndn {
+namespace gep {
+
+/**
+ * @brief ConsumerDB is a class to manage decryption keys for consumer.
+ */
+class ConsumerDB
+{
+public:
+  class Error : public std::runtime_error
+  {
+  public:
+    explicit
+    Error(const std::string& what)
+      : std::runtime_error(what)
+    {
+    }
+  };
+
+public:
+  explicit
+  ConsumerDB(const std::string& dbDir);
+
+  ~ConsumerDB();
+
+public:
+  /**
+   * @brief Get the key with @p keyName from database.
+   *
+   * @return Empty buffer when there is no key with @p keyName in database
+   */
+  const Buffer
+  getKey(const Name& keyName) const;
+
+  /**
+   * @brief Add the key with @p keyName and @p keyBuf to database.
+   *
+   * @throw Error when a key with the same name already exists in database.
+   */
+  void
+  addKey(const Name& keyName, const Buffer& keyBuf);
+
+  /**
+   * @brief Remove the key with @p keyName from the database.
+   */
+  void
+  deleteKey(const Name& keyName);
+
+private:
+  class Impl;
+  unique_ptr<Impl> m_impl;
+};
+
+} // namespace gep
+} // namespace ndn
+
+#endif // NDN_GEP_CONSUMER_DB_HPP