diff --git a/src/common.hpp b/src/common.hpp
index 675b17a..4b39994 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -22,7 +22,7 @@
 
 #include "config.hpp"
 
-#ifdef WITH_TESTS
+#ifdef NDN_GEP_HAVE_TESTS
 #define VIRTUAL_WITH_TESTS virtual
 #define PUBLIC_WITH_TESTS_ELSE_PROTECTED public
 #define PUBLIC_WITH_TESTS_ELSE_PRIVATE public
diff --git a/src/group-manager-db.cpp b/src/group-manager-db.cpp
index 7a955b5..ec0473d 100644
--- a/src/group-manager-db.cpp
+++ b/src/group-manager-db.cpp
@@ -20,6 +20,7 @@
  */
 
 #include "group-manager-db.hpp"
+#include "algo/rsa.hpp"
 
 #include <sqlite3.h>
 #include <boost/filesystem.hpp>
@@ -46,7 +47,8 @@
   "    member_id           INTEGER PRIMARY KEY,       \n"
   "    schedule_id         INTEGER NOT NULL,          \n"
   "    member_name         BLOB NOT NULL,             \n"
-  "    member_cert         BLOB NOT NULL,             \n"
+  "    key_name            BLOB NOT NULL,             \n"
+  "    pubkey              BLOB NOT NULL,             \n"
   "    FOREIGN KEY(schedule_id)                       \n"
   "      REFERENCES schedules(schedule_id)            \n"
   "      ON DELETE CASCADE                            \n"
@@ -155,21 +157,24 @@
   return result;
 }
 
-std::map<Name, Data>
+std::map<Name, Buffer>
 GroupManagerDB::getScheduleMembers(const std::string& name) const
 {
-  std::map<Name, Data> result;
+  std::map<Name, Buffer> result;
   Sqlite3Statement statement(m_impl->m_database,
-                             "SELECT member_name, member_cert\
+                             "SELECT key_name, pubkey\
                               FROM members JOIN schedules\
                               ON members.schedule_id=schedules.schedule_id\
                               WHERE schedule_name=?");
   statement.bind(1, name, SQLITE_TRANSIENT);
-
   result.clear();
+
+  const uint8_t* keyBytes = nullptr;
   while (statement.step() == SQLITE_ROW) {
-    result.insert(std::pair<Name, Data>(Name(statement.getBlock(0)),
-                                        Data(statement.getBlock(1))));
+    keyBytes = statement.getBlob(1);
+    const int& keyBytesSize = statement.getSize(1);
+    result.insert(std::pair<Name, Buffer>(Name(statement.getBlock(0)),
+                                          Buffer(keyBytes, keyBytesSize)));
   }
   return result;
 }
@@ -248,22 +253,6 @@
   return result;
 }
 
-Data
-GroupManagerDB::getMemberCert(const Name& identity) const
-{
-  Sqlite3Statement statement(m_impl->m_database,
-                             "SELECT member_cert FROM members WHERE member_name=?");
-  statement.bind(1, identity.wireEncode(), SQLITE_TRANSIENT);
-  Data result;
-  if (statement.step() == SQLITE_ROW) {
-    result.wireDecode(statement.getBlock(0));
-  }
-  else {
-    BOOST_THROW_EXCEPTION(Error("Cannot get the result from database"));
-  }
-  return result;
-}
-
 std::string
 GroupManagerDB::getMemberSchedule(const Name& identity) const
 {
@@ -285,21 +274,24 @@
 }
 
 void
-GroupManagerDB::addMember(const std::string& scheduleName, const Data& certificate)
+GroupManagerDB::addMember(const std::string& scheduleName, const Name& keyName,
+                          const Buffer& key)
 {
   int scheduleId = m_impl->getScheduleId(scheduleName);
   if (scheduleId == -1)
     BOOST_THROW_EXCEPTION(Error("The schedule dose not exist"));
 
-  IdentityCertificate cert(certificate);
-  Name memberName = cert.getPublicKeyName().getPrefix(-1);
+  // need to be changed in the future
+  Name memberName = keyName.getPrefix(-1);
 
   Sqlite3Statement statement(m_impl->m_database,
-                             "INSERT INTO members(schedule_id, member_name, member_cert)\
-                              values (?, ?, ?)");
+                             "INSERT INTO members(schedule_id, member_name, key_name, pubkey)\
+                              values (?, ?, ?, ?)");
   statement.bind(1, scheduleId);
   statement.bind(2, memberName.wireEncode(), SQLITE_TRANSIENT);
-  statement.bind(3, certificate.wireEncode(), SQLITE_TRANSIENT);
+  statement.bind(3, keyName.wireEncode(), SQLITE_TRANSIENT);
+  statement.bind(4, key.buf(), key.size(), SQLITE_TRANSIENT);
+
   if (statement.step() != SQLITE_DONE)
     BOOST_THROW_EXCEPTION(Error("Cannot add the member to database"));
 }
diff --git a/src/group-manager-db.hpp b/src/group-manager-db.hpp
index e64d677..bf5ef2f 100644
--- a/src/group-manager-db.hpp
+++ b/src/group-manager-db.hpp
@@ -75,10 +75,9 @@
   getSchedule(const std::string& name) const;
 
   /**
-   * @brief Get member information of a schedule with @p name.
-   * The member information include member name and certificate.
+   * @brief Get member key name and public key buffer of a schedule with @p name.
    */
-  std::map<Name, Data>
+  std::map<Name, Buffer>
   getScheduleMembers(const std::string& name) const;
 
   /**
@@ -129,14 +128,6 @@
   listAllMembers() const;
 
   /**
-   * @brief Get the certificate of the member with name @p identity
-   *
-   * @throw Error if there is no member with name @p identity in database
-   */
-  Data
-  getMemberCert(const Name& identity) const;
-
-  /**
    * @brief Get the schedule name of a member with name @p identity
    *
    * @throw Error if there is no member with name @p identity in database
@@ -145,13 +136,15 @@
   getMemberSchedule(const Name& identity) const;
 
   /**
-   * @brief Add a new member with @p certificate into a schedule with name @p scheduleName.
+   * @brief Add a new member with @p key of @p keyName
+   *        into a schedule with name @p scheduleName.
    *
    * @throw Error when there's no schedule named @p scheduleName
-   * @throw Error if add operation fails, e.g., a member with the same name exists
+   * @throw Error if add operation fails, e.g., the added member exists
    */
   void
-  addMember(const std::string& scheduleName, const Data& certificate);
+  addMember(const std::string& scheduleName, const Name& keyName,
+            const Buffer& key);
 
   /**
    * @brief Change the schedule of a member with name @p identity to a schedule with @p scheduleName
diff --git a/src/group-manager.cpp b/src/group-manager.cpp
new file mode 100644
index 0000000..587c488
--- /dev/null
+++ b/src/group-manager.cpp
@@ -0,0 +1,207 @@
+/* -*- 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>
+ */
+
+#include "group-manager.hpp"
+#include "encryptor.hpp"
+#include "encrypted-content.hpp"
+
+#include <map>
+
+namespace ndn {
+namespace gep {
+
+static const std::string E_KEY_COMPONENT = "E-KEY";
+static const std::string D_KEY_COMPONENT = "D-KEY";
+
+GroupManager::GroupManager(const Name& managedNamespace, const std::string& dbDir,
+                           const int paramLength, const int freshPeriod)
+  : m_namespace(managedNamespace)
+  , m_db(dbDir)
+  , m_paramLength(paramLength)
+  , m_freshPeriod(freshPeriod)
+{
+}
+
+std::list<Data>
+GroupManager::getGroupKey(const TimeStamp& timeslot)
+{
+  std::map<Name, Buffer> memberKeys;
+  std::list<Data> result;
+
+  // get time interval
+  Interval finalInterval = calculateInterval(timeslot, memberKeys);
+  if (finalInterval.isValid() == false)
+    return result;
+
+  std::string startTs = boost::posix_time::to_iso_string(finalInterval.getStartTime());
+  std::string endTs = boost::posix_time::to_iso_string(finalInterval.getEndTime());
+
+  // generate the pri key and pub key
+  Buffer priKeyBuf, pubKeyBuf;
+  generateKeyPairs(priKeyBuf, pubKeyBuf);
+
+  // add the first element to the result
+  // E-KEY (public key) data packet name convention:
+  // /<data_type>/E-KEY/[start-ts]/[end-ts]
+  Data data = createEKeyData(startTs, endTs, pubKeyBuf);
+  result.push_back(data);
+
+  // encrypt pri key with pub key from certificate
+  for (const auto& entry : memberKeys) {
+    const Name& keyName = entry.first;
+    const Buffer& certKey = entry.second;
+
+    // generate the name of the packet
+    // D-KEY (private key) data packet name convention:
+    // /<data_type>/D-KEY/[start-ts]/[end-ts]/[member-name]
+    data = createDKeyData(startTs, endTs, keyName, priKeyBuf, certKey);
+    result.push_back(data);
+  }
+  return result;
+}
+
+void
+GroupManager::addSchedule(const std::string& scheduleName, const Schedule& schedule)
+{
+  m_db.addSchedule(scheduleName, schedule);
+}
+
+void
+GroupManager::deleteSchedule(const std::string& scheduleName)
+{
+  m_db.deleteSchedule(scheduleName);
+}
+
+void
+GroupManager::updateSchedule(const std::string& scheduleName, const Schedule& schedule)
+{
+  m_db.updateSchedule(scheduleName, schedule);
+}
+
+void
+GroupManager::addMember(const std::string& scheduleName, const Data& memCert)
+{
+  IdentityCertificate cert(memCert);
+  m_db.addMember(scheduleName, cert.getPublicKeyName(), cert.getPublicKeyInfo().get());
+}
+
+void
+GroupManager::removeMember(const Name& identity)
+{
+  m_db.deleteMember(identity);
+}
+
+void
+GroupManager::updateMemberSchedule(const Name& identity, const std::string& scheduleName)
+{
+  m_db.updateMemberSchedule(identity, scheduleName);
+}
+
+Interval
+GroupManager::calculateInterval(const TimeStamp& timeslot, std::map<Name, Buffer>& memberKeys)
+{
+  // prepare
+  Interval positiveResult;
+  Interval negativeResult;
+  Interval tempInterval;
+  Interval finalInterval;
+  bool isPositive;
+  memberKeys.clear();
+
+  // get the all intervals from schedules
+  for (const std::string& scheduleName : m_db.listAllScheduleNames()) {
+
+    const Schedule& schedule = m_db.getSchedule(scheduleName);
+    std::tie(isPositive, tempInterval) = schedule.getCoveringInterval(timeslot);
+
+    if (isPositive) {
+      if (!positiveResult.isValid())
+        positiveResult = tempInterval;
+      positiveResult && tempInterval;
+
+      std::map<Name, Buffer> m = m_db.getScheduleMembers(scheduleName);
+      memberKeys.insert(m.begin(), m.end());
+    }
+    else {
+      if (!negativeResult.isValid())
+        negativeResult = tempInterval;
+      negativeResult && tempInterval;
+    }
+  }
+  if (!positiveResult.isValid()) {
+    // return invalid interval when there is no member has interval covering the time slot
+    return Interval(false);
+  }
+
+  // get the final interval result
+  if (negativeResult.isValid())
+    finalInterval = positiveResult && negativeResult;
+  else
+    finalInterval = positiveResult;
+
+  return finalInterval;
+}
+
+void
+GroupManager::generateKeyPairs(Buffer& priKeyBuf, Buffer& pubKeyBuf) const
+{
+  RandomNumberGenerator rng;
+  RsaKeyParams params(m_paramLength);
+  algo::EncryptParams eparams(tlv::AlgorithmRsaPkcs);
+  DecryptKey<algo::Rsa> privateKey = algo::Rsa::generateKey(rng, params);
+  priKeyBuf = privateKey.getKeyBits();
+  EncryptKey<algo::Rsa> publicKey = algo::Rsa::deriveEncryptKey(priKeyBuf);
+  pubKeyBuf = publicKey.getKeyBits();
+}
+
+
+Data
+GroupManager::createEKeyData(const std::string& startTs, const std::string& endTs,
+                             const Buffer& pubKeyBuf)
+{
+  Name dataName(m_namespace);
+  dataName.append(E_KEY_COMPONENT).append(startTs).append(endTs);
+  Data data(dataName);
+  data.setFreshnessPeriod(time::hours(m_freshPeriod));
+  data.setContent(pubKeyBuf.get(), pubKeyBuf.size());
+  m_keyChain.sign(data);
+  return data;
+}
+
+Data
+GroupManager::createDKeyData(const std::string& startTs, const std::string& endTs,
+                             const Name& keyName, const Buffer& priKeyBuf,
+                             const Buffer& certKey)
+{
+  Name dataName(m_namespace);
+  dataName.append(D_KEY_COMPONENT);
+  dataName.append(startTs).append(endTs).append(keyName.getPrefix(-1));
+  Data data = Data(dataName);
+  data.setFreshnessPeriod(time::hours(m_freshPeriod));
+  algo::EncryptParams eparams(tlv::AlgorithmRsaPkcs);
+  algo::encryptData(data, priKeyBuf.buf(), priKeyBuf.size(), keyName,
+                    certKey.buf(), certKey.size(), eparams);
+  m_keyChain.sign(data);
+  return data;
+}
+
+} // namespace ndn
+} // namespace ndn
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
diff --git a/tests/unit-tests/group-manager-db.t.cpp b/tests/unit-tests/group-manager-db.t.cpp
index 2c23fab..a5807f2 100644
--- a/tests/unit-tests/group-manager-db.t.cpp
+++ b/tests/unit-tests/group-manager-db.t.cpp
@@ -20,6 +20,7 @@
  */
 
 #include "group-manager-db.hpp"
+#include "algo/rsa.hpp"
 #include "boost-test.hpp"
 
 #include <boost/filesystem.hpp>
@@ -28,57 +29,57 @@
 namespace gep {
 namespace tests {
 
-const uint8_t DATA[] = {
-0x06, 0xfd, 0x02, 0xd7, 0x07, 0x38, 0x08, 0x03, 0x6e, 0x64, 0x6e, 0x08, 0x03, 0x4b, 0x45,
-0x59, 0x08, 0x05, 0x73, 0x69, 0x74, 0x65, 0x31, 0x08, 0x11, 0x6b, 0x73, 0x6b, 0x2d, 0x31,
-0x34, 0x31, 0x36, 0x34, 0x32, 0x35, 0x33, 0x37, 0x37, 0x30, 0x39, 0x34, 0x08, 0x07, 0x49,
-0x44, 0x2d, 0x43, 0x45, 0x52, 0x54, 0x08, 0x09, 0xfd, 0x00, 0x00, 0x01, 0x49, 0xc9, 0x8b,
-0x2e, 0x73, 0x14, 0x03, 0x18, 0x01, 0x02, 0x15, 0xfd, 0x01, 0x61, 0x30, 0x82, 0x01, 0x5d,
-0x30, 0x22, 0x18, 0x0f, 0x32, 0x30, 0x31, 0x34, 0x31, 0x31, 0x31, 0x39, 0x31, 0x39, 0x33,
-0x33, 0x30, 0x32, 0x5a, 0x18, 0x0f, 0x32, 0x30, 0x31, 0x35, 0x31, 0x31, 0x31, 0x39, 0x31,
-0x39, 0x33, 0x33, 0x30, 0x32, 0x5a, 0x30, 0x13, 0x30, 0x11, 0x06, 0x03, 0x55, 0x04, 0x29,
-0x13, 0x0a, 0x2f, 0x6e, 0x64, 0x6e, 0x2f, 0x73, 0x69, 0x74, 0x65, 0x31, 0x30, 0x82, 0x01,
-0x20, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05,
-0x00, 0x03, 0x82, 0x01, 0x0d, 0x00, 0x30, 0x82, 0x01, 0x08, 0x02, 0x82, 0x01, 0x01, 0x00,
-0xb6, 0x54, 0x7e, 0xe8, 0xf2, 0x91, 0x7d, 0xc1, 0x6d, 0xcb, 0x25, 0x44, 0x97, 0x90, 0xdc,
-0x78, 0x15, 0x0e, 0xef, 0xb5, 0xe7, 0xfd, 0x09, 0x2c, 0xf8, 0xd5, 0x9c, 0x2f, 0xe5, 0xa6,
-0xae, 0x9d, 0x7e, 0x95, 0x2d, 0xfc, 0xc7, 0xc3, 0x43, 0x46, 0xb0, 0x6f, 0x53, 0xcd, 0xcd,
-0x6a, 0x29, 0x1d, 0x95, 0xa1, 0x62, 0xcd, 0xa9, 0xf2, 0xf8, 0xe2, 0xfa, 0x8b, 0x5d, 0xfe,
-0xa1, 0x2b, 0x15, 0x3f, 0x7f, 0x71, 0xe6, 0x3e, 0xb9, 0xb1, 0x29, 0xd1, 0x22, 0x6f, 0x56,
-0xdf, 0xb6, 0x85, 0xaf, 0xd4, 0xb3, 0x67, 0x8b, 0x94, 0xb8, 0x83, 0xcb, 0x72, 0x86, 0xc4,
-0xf2, 0x86, 0xb2, 0x7c, 0x94, 0xbc, 0x38, 0x7b, 0x8c, 0x92, 0x86, 0x36, 0x83, 0x0e, 0x11,
-0x8c, 0x95, 0x49, 0xff, 0xcc, 0x16, 0x62, 0xdb, 0x55, 0x40, 0x7f, 0xc8, 0x8d, 0xe4, 0x3f,
-0x87, 0x02, 0x87, 0xaf, 0xf6, 0x2f, 0x8a, 0x7d, 0x74, 0x10, 0xd3, 0xbb, 0xa3, 0xfe, 0x5a,
-0x7b, 0x8f, 0x56, 0x09, 0x8b, 0x49, 0x46, 0x9f, 0x7d, 0x55, 0xa3, 0x4a, 0xe8, 0x22, 0x7b,
-0x80, 0x8a, 0x6f, 0xde, 0x9f, 0xfb, 0x2f, 0xeb, 0xf7, 0x29, 0x8a, 0x38, 0x67, 0x41, 0xae,
-0x21, 0x7a, 0xe3, 0x7b, 0x96, 0x1a, 0x90, 0x35, 0x7d, 0x04, 0xaa, 0x4d, 0x9f, 0xe6, 0xd6,
-0x00, 0x17, 0x4e, 0x02, 0x34, 0x6c, 0x56, 0x3a, 0x81, 0x3c, 0xb4, 0x7f, 0x98, 0x48, 0x22,
-0xa0, 0x9f, 0x53, 0x35, 0xf9, 0x4e, 0xae, 0x8f, 0xc3, 0xfa, 0x0b, 0x93, 0xd4, 0x55, 0x78,
-0x05, 0xb0, 0x40, 0x44, 0x48, 0x74, 0xb7, 0x9b, 0x2d, 0x65, 0xf0, 0x3d, 0x2e, 0x87, 0x2b,
-0x48, 0x29, 0x12, 0x85, 0xf0, 0xaf, 0xc4, 0xdc, 0x73, 0xce, 0x18, 0x8b, 0xd9, 0x4c, 0x60,
-0x15, 0x51, 0xae, 0x47, 0x1e, 0x2b, 0x54, 0xde, 0xf6, 0xba, 0x77, 0x30, 0x5d, 0x68, 0x9a,
-0xfb, 0x02, 0x01, 0x11, 0x16, 0x2d, 0x1b, 0x01, 0x01, 0x1c, 0x28, 0x07, 0x26, 0x08, 0x03,
-0x6e, 0x64, 0x6e, 0x08, 0x03, 0x4b, 0x45, 0x59, 0x08, 0x11, 0x6b, 0x73, 0x6b, 0x2d, 0x31,
-0x34, 0x31, 0x36, 0x34, 0x32, 0x35, 0x32, 0x39, 0x35, 0x35, 0x34, 0x36, 0x08, 0x07, 0x49,
-0x44, 0x2d, 0x43, 0x45, 0x52, 0x54, 0x17, 0xfd, 0x01, 0x00, 0x26, 0x40, 0xbc, 0xf0, 0x28,
-0x12, 0x69, 0x94, 0x11, 0x13, 0xff, 0x47, 0x2c, 0x6b, 0x12, 0xdd, 0xfa, 0x60, 0x92, 0xe9,
-0x59, 0x10, 0x98, 0xd8, 0x11, 0x2a, 0xf0, 0x25, 0xb0, 0x03, 0xb2, 0xda, 0xd3, 0xb6, 0xa9,
-0xfb, 0x8b, 0xc3, 0x6f, 0xfb, 0xb4, 0x93, 0x9b, 0x24, 0x9f, 0x7e, 0x63, 0x8a, 0x37, 0xea,
-0x88, 0x74, 0xac, 0x0c, 0x04, 0x5b, 0xa2, 0x39, 0x0c, 0xa1, 0x9e, 0x0e, 0xa2, 0xd6, 0x74,
-0xca, 0xc4, 0x92, 0x64, 0x9f, 0xc2, 0x68, 0x56, 0xef, 0xc5, 0x11, 0xe8, 0x7a, 0xf3, 0x21,
-0xde, 0x88, 0x40, 0x70, 0x2b, 0x44, 0xe0, 0xcb, 0x3b, 0x33, 0xc6, 0x53, 0x65, 0x70, 0x56,
-0x08, 0xe2, 0x22, 0x70, 0x9e, 0xe0, 0x38, 0x18, 0xa8, 0x7c, 0x7d, 0x09, 0x15, 0xac, 0xf1,
-0x44, 0x63, 0x5d, 0xd5, 0x59, 0xf4, 0xeb, 0x60, 0x6c, 0x6e, 0x77, 0x36, 0x20, 0x2a, 0xe2,
-0xd1, 0x2d, 0xa1, 0x7d, 0xd4, 0x6d, 0x29, 0x2d, 0x88, 0xde, 0x9e, 0xf8, 0x64, 0x41, 0x6a,
-0xeb, 0x9f, 0x3b, 0x52, 0x06, 0xb1, 0x94, 0x09, 0x3b, 0xc9, 0xba, 0xa0, 0x05, 0x31, 0x2d,
-0x49, 0x17, 0x5b, 0xc1, 0x62, 0xf5, 0x19, 0xce, 0x27, 0x7b, 0xe8, 0x4b, 0xeb, 0x80, 0x36,
-0xf3, 0xd7, 0xe9, 0x59, 0x22, 0x50, 0x5a, 0x14, 0xb0, 0x1a, 0xa5, 0x6b, 0x33, 0xb2, 0x83,
-0x72, 0x11, 0xf4, 0xd5, 0xd2, 0x32, 0x93, 0x94, 0xb6, 0x8d, 0xed, 0xcd, 0xce, 0x54, 0x79,
-0xe8, 0xc3, 0x3c, 0xa8, 0xc6, 0x71, 0xa7, 0x61, 0xba, 0x70, 0x44, 0x94, 0xc9, 0xfc, 0xd0,
-0x20, 0x00, 0x87, 0xdc, 0xf3, 0x3c, 0x47, 0x1b, 0x4f, 0x91, 0x4c, 0xc7, 0x49, 0xb7, 0xe4,
-0xe3, 0x84, 0xb7, 0x82, 0x52, 0xec, 0x91, 0xa9, 0x28, 0x38, 0x2d, 0x48, 0x89, 0xc7, 0xcf,
-0xfa, 0x63, 0x0b, 0xf0, 0x62, 0x51, 0xac, 0xe9, 0xdb, 0xfd, 0x1c
-};
+// const uint8_t DATA[] = {
+// 0x06, 0xfd, 0x02, 0xd7, 0x07, 0x38, 0x08, 0x03, 0x6e, 0x64, 0x6e, 0x08, 0x03, 0x4b, 0x45,
+// 0x59, 0x08, 0x05, 0x73, 0x69, 0x74, 0x65, 0x31, 0x08, 0x11, 0x6b, 0x73, 0x6b, 0x2d, 0x31,
+// 0x34, 0x31, 0x36, 0x34, 0x32, 0x35, 0x33, 0x37, 0x37, 0x30, 0x39, 0x34, 0x08, 0x07, 0x49,
+// 0x44, 0x2d, 0x43, 0x45, 0x52, 0x54, 0x08, 0x09, 0xfd, 0x00, 0x00, 0x01, 0x49, 0xc9, 0x8b,
+// 0x2e, 0x73, 0x14, 0x03, 0x18, 0x01, 0x02, 0x15, 0xfd, 0x01, 0x61, 0x30, 0x82, 0x01, 0x5d,
+// 0x30, 0x22, 0x18, 0x0f, 0x32, 0x30, 0x31, 0x34, 0x31, 0x31, 0x31, 0x39, 0x31, 0x39, 0x33,
+// 0x33, 0x30, 0x32, 0x5a, 0x18, 0x0f, 0x32, 0x30, 0x31, 0x35, 0x31, 0x31, 0x31, 0x39, 0x31,
+// 0x39, 0x33, 0x33, 0x30, 0x32, 0x5a, 0x30, 0x13, 0x30, 0x11, 0x06, 0x03, 0x55, 0x04, 0x29,
+// 0x13, 0x0a, 0x2f, 0x6e, 0x64, 0x6e, 0x2f, 0x73, 0x69, 0x74, 0x65, 0x31, 0x30, 0x82, 0x01,
+// 0x20, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05,
+// 0x00, 0x03, 0x82, 0x01, 0x0d, 0x00, 0x30, 0x82, 0x01, 0x08, 0x02, 0x82, 0x01, 0x01, 0x00,
+// 0xb6, 0x54, 0x7e, 0xe8, 0xf2, 0x91, 0x7d, 0xc1, 0x6d, 0xcb, 0x25, 0x44, 0x97, 0x90, 0xdc,
+// 0x78, 0x15, 0x0e, 0xef, 0xb5, 0xe7, 0xfd, 0x09, 0x2c, 0xf8, 0xd5, 0x9c, 0x2f, 0xe5, 0xa6,
+// 0xae, 0x9d, 0x7e, 0x95, 0x2d, 0xfc, 0xc7, 0xc3, 0x43, 0x46, 0xb0, 0x6f, 0x53, 0xcd, 0xcd,
+// 0x6a, 0x29, 0x1d, 0x95, 0xa1, 0x62, 0xcd, 0xa9, 0xf2, 0xf8, 0xe2, 0xfa, 0x8b, 0x5d, 0xfe,
+// 0xa1, 0x2b, 0x15, 0x3f, 0x7f, 0x71, 0xe6, 0x3e, 0xb9, 0xb1, 0x29, 0xd1, 0x22, 0x6f, 0x56,
+// 0xdf, 0xb6, 0x85, 0xaf, 0xd4, 0xb3, 0x67, 0x8b, 0x94, 0xb8, 0x83, 0xcb, 0x72, 0x86, 0xc4,
+// 0xf2, 0x86, 0xb2, 0x7c, 0x94, 0xbc, 0x38, 0x7b, 0x8c, 0x92, 0x86, 0x36, 0x83, 0x0e, 0x11,
+// 0x8c, 0x95, 0x49, 0xff, 0xcc, 0x16, 0x62, 0xdb, 0x55, 0x40, 0x7f, 0xc8, 0x8d, 0xe4, 0x3f,
+// 0x87, 0x02, 0x87, 0xaf, 0xf6, 0x2f, 0x8a, 0x7d, 0x74, 0x10, 0xd3, 0xbb, 0xa3, 0xfe, 0x5a,
+// 0x7b, 0x8f, 0x56, 0x09, 0x8b, 0x49, 0x46, 0x9f, 0x7d, 0x55, 0xa3, 0x4a, 0xe8, 0x22, 0x7b,
+// 0x80, 0x8a, 0x6f, 0xde, 0x9f, 0xfb, 0x2f, 0xeb, 0xf7, 0x29, 0x8a, 0x38, 0x67, 0x41, 0xae,
+// 0x21, 0x7a, 0xe3, 0x7b, 0x96, 0x1a, 0x90, 0x35, 0x7d, 0x04, 0xaa, 0x4d, 0x9f, 0xe6, 0xd6,
+// 0x00, 0x17, 0x4e, 0x02, 0x34, 0x6c, 0x56, 0x3a, 0x81, 0x3c, 0xb4, 0x7f, 0x98, 0x48, 0x22,
+// 0xa0, 0x9f, 0x53, 0x35, 0xf9, 0x4e, 0xae, 0x8f, 0xc3, 0xfa, 0x0b, 0x93, 0xd4, 0x55, 0x78,
+// 0x05, 0xb0, 0x40, 0x44, 0x48, 0x74, 0xb7, 0x9b, 0x2d, 0x65, 0xf0, 0x3d, 0x2e, 0x87, 0x2b,
+// 0x48, 0x29, 0x12, 0x85, 0xf0, 0xaf, 0xc4, 0xdc, 0x73, 0xce, 0x18, 0x8b, 0xd9, 0x4c, 0x60,
+// 0x15, 0x51, 0xae, 0x47, 0x1e, 0x2b, 0x54, 0xde, 0xf6, 0xba, 0x77, 0x30, 0x5d, 0x68, 0x9a,
+// 0xfb, 0x02, 0x01, 0x11, 0x16, 0x2d, 0x1b, 0x01, 0x01, 0x1c, 0x28, 0x07, 0x26, 0x08, 0x03,
+// 0x6e, 0x64, 0x6e, 0x08, 0x03, 0x4b, 0x45, 0x59, 0x08, 0x11, 0x6b, 0x73, 0x6b, 0x2d, 0x31,
+// 0x34, 0x31, 0x36, 0x34, 0x32, 0x35, 0x32, 0x39, 0x35, 0x35, 0x34, 0x36, 0x08, 0x07, 0x49,
+// 0x44, 0x2d, 0x43, 0x45, 0x52, 0x54, 0x17, 0xfd, 0x01, 0x00, 0x26, 0x40, 0xbc, 0xf0, 0x28,
+// 0x12, 0x69, 0x94, 0x11, 0x13, 0xff, 0x47, 0x2c, 0x6b, 0x12, 0xdd, 0xfa, 0x60, 0x92, 0xe9,
+// 0x59, 0x10, 0x98, 0xd8, 0x11, 0x2a, 0xf0, 0x25, 0xb0, 0x03, 0xb2, 0xda, 0xd3, 0xb6, 0xa9,
+// 0xfb, 0x8b, 0xc3, 0x6f, 0xfb, 0xb4, 0x93, 0x9b, 0x24, 0x9f, 0x7e, 0x63, 0x8a, 0x37, 0xea,
+// 0x88, 0x74, 0xac, 0x0c, 0x04, 0x5b, 0xa2, 0x39, 0x0c, 0xa1, 0x9e, 0x0e, 0xa2, 0xd6, 0x74,
+// 0xca, 0xc4, 0x92, 0x64, 0x9f, 0xc2, 0x68, 0x56, 0xef, 0xc5, 0x11, 0xe8, 0x7a, 0xf3, 0x21,
+// 0xde, 0x88, 0x40, 0x70, 0x2b, 0x44, 0xe0, 0xcb, 0x3b, 0x33, 0xc6, 0x53, 0x65, 0x70, 0x56,
+// 0x08, 0xe2, 0x22, 0x70, 0x9e, 0xe0, 0x38, 0x18, 0xa8, 0x7c, 0x7d, 0x09, 0x15, 0xac, 0xf1,
+// 0x44, 0x63, 0x5d, 0xd5, 0x59, 0xf4, 0xeb, 0x60, 0x6c, 0x6e, 0x77, 0x36, 0x20, 0x2a, 0xe2,
+// 0xd1, 0x2d, 0xa1, 0x7d, 0xd4, 0x6d, 0x29, 0x2d, 0x88, 0xde, 0x9e, 0xf8, 0x64, 0x41, 0x6a,
+// 0xeb, 0x9f, 0x3b, 0x52, 0x06, 0xb1, 0x94, 0x09, 0x3b, 0xc9, 0xba, 0xa0, 0x05, 0x31, 0x2d,
+// 0x49, 0x17, 0x5b, 0xc1, 0x62, 0xf5, 0x19, 0xce, 0x27, 0x7b, 0xe8, 0x4b, 0xeb, 0x80, 0x36,
+// 0xf3, 0xd7, 0xe9, 0x59, 0x22, 0x50, 0x5a, 0x14, 0xb0, 0x1a, 0xa5, 0x6b, 0x33, 0xb2, 0x83,
+// 0x72, 0x11, 0xf4, 0xd5, 0xd2, 0x32, 0x93, 0x94, 0xb6, 0x8d, 0xed, 0xcd, 0xce, 0x54, 0x79,
+// 0xe8, 0xc3, 0x3c, 0xa8, 0xc6, 0x71, 0xa7, 0x61, 0xba, 0x70, 0x44, 0x94, 0xc9, 0xfc, 0xd0,
+// 0x20, 0x00, 0x87, 0xdc, 0xf3, 0x3c, 0x47, 0x1b, 0x4f, 0x91, 0x4c, 0xc7, 0x49, 0xb7, 0xe4,
+// 0xe3, 0x84, 0xb7, 0x82, 0x52, 0xec, 0x91, 0xa9, 0x28, 0x38, 0x2d, 0x48, 0x89, 0xc7, 0xcf,
+// 0xfa, 0x63, 0x0b, 0xf0, 0x62, 0x51, 0xac, 0xe9, 0xdb, 0xfd, 0x1c
+// };
 
 const uint8_t SCHEDULE[] = {
   0x8f, 0xc4,// Schedule
@@ -181,23 +182,23 @@
   dbDir += "/test.db";
   GroupManagerDB db(dbDir);
 
-  Block dataBlock(DATA, sizeof(DATA));
   Block scheduleBlock(SCHEDULE, sizeof(SCHEDULE));
 
   // create schedule
   Schedule schedule(scheduleBlock);
 
   // create member
-  Data data1(dataBlock);
-  data1.setName(Name("/ndn/BoyA/KEY/ksk-123/ID-CERT/123"));
-  Data data2(dataBlock);
-  data2.setName(Name("/ndn/BoyB/KEY/ksk-123/ID-CERT/123"));
-  Data data3(dataBlock);
-  data3.setName(Name("/ndn/GirlC/KEY/ksk-123/ID-CERT/123"));
-  Data data4(dataBlock);
-  data4.setName(Name("/ndn/GirlD/KEY/ksk-123/ID-CERT/123"));
-  Data data5(dataBlock);
-  data5.setName(Name("/ndn/Hello/KEY/ksk-123/ID-CERT/123"));
+  RandomNumberGenerator rng;
+  RsaKeyParams params;
+  DecryptKey<algo::Rsa> decryptKey = algo::Rsa::generateKey(rng, params);
+  EncryptKey<algo::Rsa> encryptKey = algo::Rsa::deriveEncryptKey(decryptKey.getKeyBits());
+  Buffer keyBuf = encryptKey.getKeyBits();
+
+  Name name1("/ndn/BoyA/ksk-123");
+  Name name2("/ndn/BoyB/ksk-1233");
+  Name name3("/ndn/GirlC/ksk-123");
+  Name name4("/ndn/GirlD/ksk-123");
+  Name name5("/ndn/Hello/ksk-123");
 
   // add schedules into the database
   BOOST_CHECK_NO_THROW(db.addSchedule("work-time", schedule));
@@ -209,18 +210,18 @@
   BOOST_CHECK_THROW(db.addSchedule("boelter-time", schedule), GroupManagerDB::Error);
 
   // add members into the database
-  BOOST_CHECK_NO_THROW(db.addMember("work-time", data1));
-  BOOST_CHECK_NO_THROW(db.addMember("rest-time", data2));
-  BOOST_CHECK_NO_THROW(db.addMember("play-time", data3));
-  BOOST_CHECK_NO_THROW(db.addMember("play-time", data4));
+  BOOST_CHECK_NO_THROW(db.addMember("work-time", name1, keyBuf));
+  BOOST_CHECK_NO_THROW(db.addMember("rest-time", name2, keyBuf));
+  BOOST_CHECK_NO_THROW(db.addMember("play-time", name3, keyBuf));
+  BOOST_CHECK_NO_THROW(db.addMember("play-time", name4, keyBuf));
 
   // throw exception when adding a member having a not existing schedule name
-  BOOST_CHECK_THROW(db.addMember("false-time", data5), GroupManagerDB::Error);
+  BOOST_CHECK_THROW(db.addMember("false-time", name5, keyBuf), GroupManagerDB::Error);
 
-  BOOST_CHECK_NO_THROW(db.addMember("boelter-time", data5));
+  BOOST_CHECK_NO_THROW(db.addMember("boelter-time", name5, keyBuf));
 
   // throw exception when adding a member having an existing identity
-  BOOST_CHECK_THROW(db.addMember("work-time", data5), GroupManagerDB::Error);
+  BOOST_CHECK_THROW(db.addMember("work-time", name5, keyBuf), GroupManagerDB::Error);
 
   // has function
   BOOST_CHECK_EQUAL(db.hasSchedule("work-time"), true);
@@ -243,16 +244,6 @@
   // throw exception when there is no such schedule in database
   BOOST_CHECK_THROW(db.getSchedule("work-time-11"), GroupManagerDB::Error);
 
-  // get certificate of a member
-  Data dataResult = db.getMemberCert(Name("/ndn/BoyA"));
-  BOOST_CHECK(dataResult.wireEncode() == data1.wireEncode());
-
-  dataResult = db.getMemberCert(Name("/ndn/GirlC"));
-  BOOST_CHECK(dataResult.wireEncode() == data3.wireEncode());
-
-  // throw error when there is no such member in database
-  BOOST_CHECK_THROW(db.getMemberCert(Name("/ndn/GirlA")), GroupManagerDB::Error);
-
   // list all schedule names
   std::list<std::string> names = db.listAllScheduleNames();
   BOOST_CHECK(std::find(names.begin(), names.end(), "work-time") != names.end());
@@ -261,7 +252,7 @@
   BOOST_CHECK(std::find(names.begin(), names.end(), "sleep-time") == names.end());
 
   // list members of a schedule
-  std::map<Name, Data> memberMap = db.getScheduleMembers("play-time");
+  std::map<Name, Buffer> memberMap = db.getScheduleMembers("play-time");
   BOOST_CHECK(memberMap.size() != 0);
 
   // when there's no such schedule, the return list's size is 0
diff --git a/tests/unit-tests/group-manager.t.cpp b/tests/unit-tests/group-manager.t.cpp
new file mode 100644
index 0000000..1d25698
--- /dev/null
+++ b/tests/unit-tests/group-manager.t.cpp
@@ -0,0 +1,354 @@
+/* -*- 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>
+ */
+
+#include "group-manager.hpp"
+#include "boost-test.hpp"
+#include "algo/rsa.hpp"
+#include "algo/aes.hpp"
+#include "encrypted-content.hpp"
+
+#include <boost/filesystem.hpp>
+#include <ndn-cxx/encoding/buffer-stream.hpp>
+#include <string>
+
+namespace ndn {
+namespace gep {
+namespace tests {
+
+using namespace boost::posix_time;
+
+const uint8_t SIG_INFO[] = {
+  0x16, 0x1b, // SignatureInfo
+      0x1b, 0x01, // SignatureType
+          0x01,
+      0x1c, 0x16, // KeyLocator
+          0x07, 0x14, // Name
+              0x08, 0x04,
+                  0x74, 0x65, 0x73, 0x74,
+              0x08, 0x03,
+                  0x6b, 0x65, 0x79,
+              0x08, 0x07,
+                  0x6c, 0x6f, 0x63, 0x61, 0x74, 0x6f, 0x72
+};
+
+const uint8_t SIG_VALUE[] = {
+  0x17, 0x80, // SignatureValue
+      0x2f, 0xd6, 0xf1, 0x6e, 0x80, 0x6f, 0x10, 0xbe, 0xb1, 0x6f, 0x3e, 0x31, 0xec,
+      0xe3, 0xb9, 0xea, 0x83, 0x30, 0x40, 0x03, 0xfc, 0xa0, 0x13, 0xd9, 0xb3, 0xc6,
+      0x25, 0x16, 0x2d, 0xa6, 0x58, 0x41, 0x69, 0x62, 0x56, 0xd8, 0xb3, 0x6a, 0x38,
+      0x76, 0x56, 0xea, 0x61, 0xb2, 0x32, 0x70, 0x1c, 0xb6, 0x4d, 0x10, 0x1d, 0xdc,
+      0x92, 0x8e, 0x52, 0xa5, 0x8a, 0x1d, 0xd9, 0x96, 0x5e, 0xc0, 0x62, 0x0b, 0xcf,
+      0x3a, 0x9d, 0x7f, 0xca, 0xbe, 0xa1, 0x41, 0x71, 0x85, 0x7a, 0x8b, 0x5d, 0xa9,
+      0x64, 0xd6, 0x66, 0xb4, 0xe9, 0x8d, 0x0c, 0x28, 0x43, 0xee, 0xa6, 0x64, 0xe8,
+      0x55, 0xf6, 0x1c, 0x19, 0x0b, 0xef, 0x99, 0x25, 0x1e, 0xdc, 0x78, 0xb3, 0xa7,
+      0xaa, 0x0d, 0x14, 0x58, 0x30, 0xe5, 0x37, 0x6a, 0x6d, 0xdb, 0x56, 0xac, 0xa3,
+      0xfc, 0x90, 0x7a, 0xb8, 0x66, 0x9c, 0x0e, 0xf6, 0xb7, 0x64, 0xd1
+};
+
+class GroupManagerFixture
+{
+public:
+  GroupManagerFixture()
+    : tmpPath(boost::filesystem::path(TMP_TESTS_PATH))
+  {
+    boost::filesystem::create_directories(tmpPath);
+
+    // generate the certificate public key
+    RandomNumberGenerator rng;
+    RsaKeyParams params;
+    DecryptKey<algo::Rsa> memberDecryptKey = algo::Rsa::generateKey(rng, params);
+    decryptKeyBuf = memberDecryptKey.getKeyBits();
+    EncryptKey<algo::Rsa> memberEncryptKey = algo::Rsa::deriveEncryptKey(decryptKeyBuf);
+    encryptKeyBuf = memberEncryptKey.getKeyBits();
+
+    // generate certificate
+    cert.setName(Name("/ndn/memberA/KEY/ksk-123/ID-CERT/123"));
+    PublicKey contentPubKey(encryptKeyBuf.buf(), encryptKeyBuf.size());
+    cert.setPublicKeyInfo(contentPubKey);
+    cert.encode();
+
+    Block sigInfoBlock(SIG_INFO, sizeof(SIG_INFO));
+    Block sigValueBlock(SIG_VALUE, sizeof(SIG_VALUE));
+
+    Signature sig(sigInfoBlock, sigValueBlock);
+    cert.setSignature(sig);
+
+    auto dataBlock = cert.wireEncode();
+  }
+
+  void
+  setManager(GroupManager& manager)
+  {
+    // set the first schedule
+    Schedule schedule1;
+    RepetitiveInterval interval11(from_iso_string("20150825T000000"),
+                                  from_iso_string("20150827T000000"),
+                                  5, 10, 2, RepetitiveInterval::RepeatUnit::DAY);
+    RepetitiveInterval interval12(from_iso_string("20150825T000000"),
+                                  from_iso_string("20150827T000000"),
+                                  6, 8, 1, RepetitiveInterval::RepeatUnit::DAY);
+    RepetitiveInterval interval13(from_iso_string("20150827T000000"),
+                                  from_iso_string("20150827T000000"),
+                                  7, 8);
+    schedule1.addWhiteInterval(interval11);
+    schedule1.addWhiteInterval(interval12);
+    schedule1.addBlackInterval(interval13);
+
+    // set the second schedule
+    Schedule schedule2;
+    RepetitiveInterval interval21(from_iso_string("20150825T000000"),
+                                  from_iso_string("20150827T000000"),
+                                  9, 12, 1, RepetitiveInterval::RepeatUnit::DAY);
+    RepetitiveInterval interval22(from_iso_string("20150827T000000"),
+                                  from_iso_string("20150827T000000"),
+                                  6, 8);
+    RepetitiveInterval interval23(from_iso_string("20150827T000000"),
+                                  from_iso_string("20150827T000000"),
+                                  2, 4);
+    schedule2.addWhiteInterval(interval21);
+    schedule2.addWhiteInterval(interval22);
+    schedule2.addBlackInterval(interval23);
+
+    // add to the group manager db
+    manager.addSchedule("schedule1", schedule1);
+    manager.addSchedule("schedule2", schedule2);
+
+    // do some adaptions to certificate
+    Block dataBlock = cert.wireEncode();
+
+    Data memberA(dataBlock);
+    memberA.setName(Name("/ndn/memberA/KEY/ksk-123/ID-CERT/123"));
+    Data memberB(dataBlock);
+    memberB.setName(Name("/ndn/memberB/KEY/ksk-123/ID-CERT/123"));
+    Data memberC(dataBlock);
+    memberC.setName(Name("/ndn/memberC/KEY/ksk-123/ID-CERT/123"));
+
+    // add members to the database
+    manager.addMember("schedule1", memberA);
+    manager.addMember("schedule1", memberB);
+    manager.addMember("schedule2", memberC);
+  }
+
+  ~GroupManagerFixture()
+  {
+    boost::filesystem::remove_all(tmpPath);
+  }
+
+public:
+  boost::filesystem::path tmpPath;
+  Buffer decryptKeyBuf;
+  Buffer encryptKeyBuf;
+  IdentityCertificate cert;
+};
+
+BOOST_FIXTURE_TEST_SUITE(TestGroupManager, GroupManagerFixture)
+
+BOOST_AUTO_TEST_CASE(CreateDKeyData)
+{
+  // create the group manager database
+  std::string dbDir = tmpPath.c_str();
+  dbDir += "/manager-d-key-test.db";
+  GroupManager manager(Name("Alice-read"), dbDir, 2048, 1);
+
+  Block newCertBlock = cert.wireEncode();
+  IdentityCertificate newCert(newCertBlock);
+
+  // encrypt D-KEY
+  Data data = manager.createDKeyData("20150825T000000", "20150827T000000", Name("/ndn/memberA/KEY"),
+                                     decryptKeyBuf, newCert.getPublicKeyInfo().get());
+
+  // verify encrypted D-KEY
+  Block dataContent = data.getContent();
+  dataContent.parse();
+  BOOST_CHECK_EQUAL(dataContent.elements_size(), 2);
+
+  // get nonce key
+  Block::element_const_iterator contentIterator = dataContent.elements_begin();
+  Block nonceContent(*contentIterator);
+  BOOST_CHECK_EQUAL(nonceContent.type(), tlv::EncryptedContent);
+  EncryptedContent encryptedNonce(nonceContent);
+  BOOST_CHECK_EQUAL(encryptedNonce.getInitialVector().size(), 0);
+  BOOST_CHECK_EQUAL(encryptedNonce.getAlgorithmType(), tlv::AlgorithmRsaPkcs);
+
+  const Buffer& bufferNonce = encryptedNonce.getPayload();
+  algo::EncryptParams decryptParams(tlv::AlgorithmRsaPkcs);
+  Buffer nonce = algo::Rsa::decrypt(decryptKeyBuf.buf(), decryptKeyBuf.size(),
+                                    bufferNonce.buf(), bufferNonce.size(), decryptParams);
+
+  // get D-KEY
+  contentIterator++;
+  Block payloadContent(*contentIterator);
+  BOOST_CHECK_EQUAL(payloadContent.type(), tlv::EncryptedContent);
+  EncryptedContent encryptedPayload(payloadContent);
+  BOOST_CHECK_EQUAL(encryptedPayload.getInitialVector().size(), 16);
+  BOOST_CHECK_EQUAL(encryptedPayload.getAlgorithmType(), tlv::AlgorithmAesCbc);
+
+  decryptParams.setAlgorithmType(tlv::AlgorithmAesCbc);
+  decryptParams.setIV(encryptedPayload.getInitialVector().buf(),
+                      encryptedPayload.getInitialVector().size());
+  const Buffer& bufferPayload = encryptedPayload.getPayload();
+  Buffer largePayload = algo::Aes::decrypt(nonce.buf(), nonce.size(),
+                                           bufferPayload.buf(), bufferPayload.size(),
+                                           decryptParams);
+
+  BOOST_CHECK_EQUAL_COLLECTIONS(largePayload.begin(), largePayload.end(),
+                                decryptKeyBuf.begin(), decryptKeyBuf.end());
+}
+
+BOOST_AUTO_TEST_CASE(CreateEKeyData)
+{
+  // create the group manager database
+  std::string dbDir = tmpPath.c_str();
+  dbDir += "/manager-e-key-test.db";
+
+  // create group manager
+  GroupManager manager(Name("Alice-read"), dbDir, 1024, 1);
+  setManager(manager);
+
+  Data data = manager.createEKeyData("20150825T090000", "20150825T110000", encryptKeyBuf);
+  BOOST_CHECK_EQUAL(data.getName().toUri(), "/Alice-read/E-KEY/20150825T090000/20150825T110000");
+
+  Buffer contentBuf(data.getContent().value(), data.getContent().value_size());
+  BOOST_CHECK_EQUAL_COLLECTIONS(encryptKeyBuf.begin(), encryptKeyBuf.end(),
+                                contentBuf.begin(), contentBuf.end());
+
+}
+
+BOOST_AUTO_TEST_CASE(CalculateInterval)
+{
+  // create the group manager database
+  std::string dbDir = tmpPath.c_str();
+  dbDir += "/manager-interval-test.db";
+
+  // create group manager
+  GroupManager manager(Name("Alice-read"), dbDir, 1024, 1);
+  setManager(manager);
+
+  std::map<Name, Buffer> memberKeys;
+  Interval result;
+
+  TimeStamp tp1(from_iso_string("20150825T093000"));
+  result = manager.calculateInterval(tp1, memberKeys);
+  BOOST_CHECK_EQUAL(to_iso_string(result.getStartTime()), "20150825T090000");
+  BOOST_CHECK_EQUAL(to_iso_string(result.getEndTime()), "20150825T100000");
+
+  TimeStamp tp2(from_iso_string("20150827T073000"));
+  result = manager.calculateInterval(tp2, memberKeys);
+  BOOST_CHECK_EQUAL(to_iso_string(result.getStartTime()), "20150827T070000");
+  BOOST_CHECK_EQUAL(to_iso_string(result.getEndTime()), "20150827T080000");
+
+  TimeStamp tp3(from_iso_string("20150827T043000"));
+  result = manager.calculateInterval(tp3, memberKeys);
+  BOOST_CHECK_EQUAL(result.isValid(), false);
+
+  TimeStamp tp4(from_iso_string("20150827T053000"));
+  result = manager.calculateInterval(tp4, memberKeys);
+  BOOST_CHECK_EQUAL(to_iso_string(result.getStartTime()), "20150827T050000");
+  BOOST_CHECK_EQUAL(to_iso_string(result.getEndTime()), "20150827T060000");
+}
+
+BOOST_AUTO_TEST_CASE(GetGroupKey)
+{
+  // create the group manager database
+  std::string dbDir = tmpPath.c_str();
+  dbDir += "/manager-group-key-test.db";
+
+  // create group manager
+  GroupManager manager(Name("Alice-read"), dbDir, 1024, 1);
+  setManager(manager);
+
+  // get data list from group manager
+  TimeStamp tp1(from_iso_string("20150825T093000"));
+  std::list<Data> result = manager.getGroupKey(tp1);
+
+  BOOST_CHECK_EQUAL(result.size(), 4);
+
+  // first data contain the group encrypt key(public key)
+  std::list<Data>::iterator dataIterator = result.begin();
+  BOOST_CHECK_EQUAL(dataIterator->getName().toUri(),
+                    "/Alice-read/E-KEY/20150825T090000/20150825T100000");
+  EncryptKey<algo::Rsa> groupEKey(Buffer(dataIterator->getContent().value(),
+                                         dataIterator->getContent().value_size()));
+
+  // second data and decrypt
+  dataIterator++;
+  BOOST_CHECK_EQUAL(dataIterator->getName().getPrefix(-2).toUri(),
+                    "/Alice-read/D-KEY/20150825T090000/20150825T100000");
+
+  //////////////////////////////////////////////////////////////////////// start decryption
+  Block dataContent = dataIterator->getContent();
+
+  dataContent.parse();
+  BOOST_CHECK_EQUAL(dataContent.elements_size(), 2);
+
+  // get nonce key
+  Block::element_const_iterator contentIterator = dataContent.elements_begin();
+  Block nonceContent(*contentIterator);
+  BOOST_CHECK_EQUAL(nonceContent.type(), tlv::EncryptedContent);
+  EncryptedContent encryptedNonce(nonceContent);
+  BOOST_CHECK_EQUAL(encryptedNonce.getInitialVector().size(), 0);
+  BOOST_CHECK_EQUAL(encryptedNonce.getAlgorithmType(), tlv::AlgorithmRsaPkcs);
+
+  algo::EncryptParams decryptParams(tlv::AlgorithmRsaPkcs);
+  const Buffer& bufferNonce = encryptedNonce.getPayload();
+  Buffer nonce = algo::Rsa::decrypt(decryptKeyBuf.buf(), decryptKeyBuf.size(),
+                                    bufferNonce.buf(), bufferNonce.size(), decryptParams);
+
+  // get buffer payload
+  contentIterator++;
+  Block payloadContent(*contentIterator);
+  BOOST_CHECK_EQUAL(payloadContent.type(), tlv::EncryptedContent);
+  EncryptedContent encryptedPayload(payloadContent);
+  BOOST_CHECK_EQUAL(encryptedPayload.getInitialVector().size(), 16);
+  BOOST_CHECK_EQUAL(encryptedPayload.getAlgorithmType(), tlv::AlgorithmAesCbc);
+
+  decryptParams.setAlgorithmType(tlv::AlgorithmAesCbc);
+  decryptParams.setIV(encryptedPayload.getInitialVector().buf(),
+                      encryptedPayload.getInitialVector().size());
+  const Buffer& bufferPayload = encryptedPayload.getPayload();
+  Buffer largePayload = algo::Aes::decrypt(nonce.buf(), nonce.size(),
+                                           bufferPayload.buf(), bufferPayload.size(),
+                                           decryptParams);
+
+  // get group D-KEY
+  DecryptKey<algo::Rsa> groupDKey(Buffer(largePayload.buf(), largePayload.size()));
+
+  /////////////////////////////////////////////////////////////////////// end decryption
+
+  // check the D-KEY
+  EncryptKey<algo::Rsa> derivedGroupEKey = algo::Rsa::deriveEncryptKey(groupDKey.getKeyBits());
+  BOOST_CHECK_EQUAL_COLLECTIONS(groupEKey.getKeyBits().begin(), groupEKey.getKeyBits().end(),
+                                derivedGroupEKey.getKeyBits().begin(),
+                                derivedGroupEKey.getKeyBits().end());
+
+  // invalid time stamp to get group key
+  TimeStamp tp2(from_iso_string("20150826T083000"));
+  BOOST_CHECK_EQUAL(manager.getGroupKey(tp2).size(), 0);
+
+  TimeStamp tp3(from_iso_string("20150827T023000"));
+  BOOST_CHECK_EQUAL(manager.getGroupKey(tp3).size(), 0);
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+} // namespace test
+} // namespace gep
+} // namespace ndn