diff --git a/src/group-manager.hpp b/src/group-manager.hpp
new file mode 100644
index 0000000..34937da
--- /dev/null
+++ b/src/group-manager.hpp
@@ -0,0 +1,128 @@
+/* -*- 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_GROUP_MANAGER_HPP
+#define NDN_GEP_GROUP_MANAGER_HPP
+
+#include "group-manager-db.hpp"
+#include "algo/rsa.hpp"
+
+#include <ndn-cxx/security/key-chain.hpp>
+
+namespace ndn {
+namespace gep {
+
+class GroupManager
+{
+public:
+  class Error : public std::runtime_error
+  {
+  public:
+    explicit
+    Error(const std::string& what)
+      : std::runtime_error(what)
+    {
+    }
+  };
+
+public:
+  /// @brief Create group manager using @p managedNamespace
+  GroupManager(const Name& managedNamespace, const std::string& dbDir,
+               const int paramLength, const int freshPeriod);
+
+  /**
+   * @brief Create a group key for interval which
+   *        @p timeslot falls into
+   *
+   * This method creates a group key if it does not
+   * exist, and encrypts the key using public key of
+   * all eligible members
+   *
+   * @returns The group key (the first one is the
+   *          public key, and the rest are encrypted
+   *          private key.
+   */
+  std::list<Data>
+  getGroupKey(const TimeStamp& timeslot);
+
+  /// @brief Add @p schedule with @p scheduleName
+  void
+  addSchedule(const std::string& scheduleName, const Schedule& schedule);
+
+  /// @brief Delete schedule with name @p scheduleName
+  void
+  deleteSchedule(const std::string& scheduleName);
+
+  /// @brief Update a schedule by name @p scheduleName with a new @p schedule
+  void
+  updateSchedule(const std::string& scheduleName, const Schedule& schedule);
+
+  /// @brief Add @p memCert with @p scheduleName
+  void
+  addMember(const std::string& scheduleName, const Data& memCert);
+
+  /// @brief Remove member with name @p identity from the group.
+  void
+  removeMember(const Name& identity);
+
+  /// @brief Update @p member with a schedule of @p schedule Name.
+  void
+  updateMemberSchedule(const Name& identity, const std::string& scheduleName);
+
+PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+  /**
+   * @brief Calculate interval that covers @p timeslot
+   * and fill @p memberKeys with the info of members who is allowed to access the interval.
+   */
+  Interval
+  calculateInterval(const TimeStamp& timeslot, std::map<Name, Buffer>& certMap);
+
+  /**
+   * @brief Generate rsa key pairs according to the member variable m_paramLength.
+   * @p priKeyBuf The generated private key buffer
+   * @p pubKeyBuf The generated public key buffer
+   */
+  void
+  generateKeyPairs(Buffer& priKeyBuf, Buffer& pubKeyBuf) const;
+
+  /// @brief Create E-KEY data.
+  Data
+  createEKeyData(const std::string& startTs, const std::string& endTs,
+                 const Buffer& pubKeyBuf);
+
+  /// @brief Create D-KEY data.
+  Data
+  createDKeyData(const std::string& startTs, const std::string& endTs, const Name& keyName,
+                 const Buffer& priKeyBuf, const Buffer& certKey);
+
+private:
+  Name m_namespace;
+  GroupManagerDB m_db;
+  int m_paramLength;
+  int m_freshPeriod;
+
+  KeyChain m_keyChain;
+};
+
+} // namespace gep
+} // namespace ndn
+
+#endif // NDN_GEP_GROUP_MANAGER_HPP