diff --git a/device_storage.py b/device_storage.py
new file mode 100644
index 0000000..3de7c54
--- /dev/null
+++ b/device_storage.py
@@ -0,0 +1,602 @@
+# -*- Mode:python; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+#
+# Copyright (C) 2014 Regents of the University of California.
+# Author: Teng Liang <philoliang2011@gmail.com> 
+# This program 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.
+#
+# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+# A copy of the GNU General Public License is in the file COPYING.
+"""
+DeviceStorage implements a basic storage of devices and corresponding commands
+"""
+
+import os
+import sqlite3
+from pyndn import Name
+from device_profile import DeviceProfile
+from hmac_key import HMACKey
+
+INIT_DEVICE_TABLE = ["""
+CREATE TABLE IF NOT EXISTS
+  Device(
+      id                             INTEGER,
+      prefix                         BLOB NOT NULL UNIQUE,
+      location                       BLOB,
+      category                       BLOB,
+      type                           BLOB,
+      model                          BLOB,
+      serial_number                  BLOB,
+      manufacturer                   BLOB,
+      seed_name                      BLOB NOT NULL,
+      seed_sequence                  INTEGER NOT NULL,
+      seed_counter                   INTEGER NOT NULL,
+      seed                           BLOB NOT NULL,
+      configuration_token            BLOB NOT NULL,
+      configuration_token_sequence   INTEGER NOT NULL,
+      configuration_token_counter    INTEGER NOT NULL,
+      
+      PRIMARY KEY (id)
+  );
+"""]
+
+INIT_COMMAND_TABLE = ["""
+CREATE TABLE IF NOT EXISTS
+  Command(
+      id                            INTEGER,
+      device_id                     INTEGER NOT NULL,
+      name                          BLOB NOT NULL,
+      command_token_name            BLOB NOT NULL,
+      command_token_sequence        INTEGER NOT NULL,
+      command_token_counter         INTEGER NOT NULL,
+      command_token                 BLOB NOT NULL,
+      
+      PRIMARY KEY(id)
+      FOREIGN KEY(device_id) REFERENCES Device(id)
+  );
+"""]
+
+INIT_SERVICE_PROFILE_TABLE = ["""
+CREATE TABLE IF NOT EXISTS
+  ServiceProfile(
+      id                            INTEGER,
+      device_id                     INTEGER NOT NULL,
+      name                          BLOB NOT NULL,
+      
+      PRIMARY KEY(id)
+      FOREIGN KEY(device_id) REFERENCES Device(id)
+  );
+"""]
+
+class DeviceStorage(object):
+    """
+    Create a new DeviceUserStorage to work with an SQLite file.
+    :param str databaseFilePath: (optional) The path of the SQLite file. If ommitted, use the default path.
+    """
+    def __init__(self, databaseFilePath = None):
+        if databaseFilePath == None or databaseFilePath == "":
+            if not "HOME" in os.environ:
+                home = '.'
+            else:
+                home = os.environ["HOME"]
+            
+            dbDirectory = os.path.join(home, '.ndn')
+            if not os.path.exists(dbDirectory):
+                os.makedirs(dbDirectory)
+
+            databaseFilePath = os.path.join(dbDirectory, 'ndnhome-controller.db')
+
+        self._database =  sqlite3.connect(databaseFilePath)
+        
+        #Check if the Device table exists
+        cursor = self._database.cursor()
+        cursor.execute("SELECT name FROM sqlite_master WHERE TYPE ='table' and NAME = 'Device'")
+        if cursor.fetchone() == None:
+            #no device table exists, create one
+            for command in INIT_DEVICE_TABLE:
+                self._database.execute(command)
+        cursor.close()
+        
+        #Check if the Command table exists
+        cursor = self._database.cursor()
+        cursor.execute("SELECT name FROM sqlite_master WHERE TYPE ='table' and NAME = 'Command'")
+        if cursor.fetchone() == None:
+            #no command table exists, create one
+            for command in INIT_COMMAND_TABLE:
+                self._database.execute(command)
+        cursor.close()
+
+        #Check if the ServiceProfile table exists
+        cursor = self._database.cursor()
+        cursor.execute("SELECT name FROM sqlite_master WHERE TYPE ='table' and NAME = 'ServiceProfile'")
+        if cursor.fetchone() == None:
+            #no ServiceProfile table exists, create one
+            for command in INIT_SERVICE_PROFILE_TABLE:
+                self._database.execute(command)
+        cursor.close()
+
+        self._database.commit()
+   
+    def doesTableExist(self, tableName):
+        """
+         check if table exists
+         :param str tableName
+         :return True if exists, otherwise False
+        """
+        selectOperation = "SELECT name FROM sqlite_master WHERE TYPE='table' and NAME='" + tableName +"'"
+        #print selectOperation
+        cursor = self._database.cursor()
+        cursor.execute(selectOperation)
+        if cursor.fetchone() == None:
+            result = False
+        else: 
+            result = True
+        cursor.close()
+        return result
+
+    def doesDeviceExist(self, prefix):
+        """
+        Check if the specified device already exists.
+       
+        :param Name prefix: the prefix of device
+        :return True if the device exists, otherwise False
+        :rtype: bool
+        """
+        result = False
+        #print prefix        
+        cursor = self._database.cursor()
+        cursor.execute("SELECT count(*) FROM Device WHERE prefix =?", (prefix.toUri(),))
+        (count,) = cursor.fetchone()
+        if count > 0:
+            result = True
+            #print 'device with %s is founnd, count %d' %(prefix, count)
+
+        cursor.close()
+        return result
+
+    def addDevice(self, deviceProfile, seed, configurationToken):
+        """ 
+        Add a new device to the Device table, do nothing if the device already exists
+        
+        :param DeviceProfile devicePorfile: the deviceProfile of the device
+        :param Key seed: the seed of the device
+        :param Key configurationToken: the configurationToken of the device
+        :return the device id if it's added successfully, 0 if the device already exists, otherwise -1
+        :rtype: INTEGER
+        """
+        result = -1
+        data = (deviceProfile.getPrefix().toUri(),
+               deviceProfile.getLocation(),
+               deviceProfile.getCategory(),
+               deviceProfile.getType(),
+               deviceProfile.getModel(),
+               deviceProfile.getManufacturer(),
+               deviceProfile.getSerialNumber(),
+               seed.getName(),
+               seed.getSequence(),
+               seed.getCounter(),
+               seed.getKey(),
+               configurationToken.getKey(),
+               configurationToken.getSequence(),
+               configurationToken.getCounter()
+              )     
+
+        #check if the device already exists, if yes return 0
+        prefixName = deviceProfile.getPrefix()
+        if self.doesDeviceExist(prefixName):
+            return 0
+
+        insertDevice = (
+            "INSERT INTO Device(prefix, location, category, type, model, manufacturer, serial_number, seed_name, seed_sequence, seed_counter,seed, configuration_token, configuration_token_sequence, configuration_token_counter)"
+            "VALUES(?,?,?,?,?,?,?,?,?,?,?,?,?,?)"
+        )
+        cursor = self._database.cursor()
+        cursor.execute(insertDevice, data)
+        self._database.commit()
+        result = cursor.lastrowid
+        cursor.close()
+        return result
+
+    def getDeviceProfileFromDevice(self, prefix):
+        """
+        get the specified device profile
+        :param Name prefix: the device prefix
+        :return device profile of the device if exists, otherwise return None
+        :rtype: DeviceProfile
+        """   
+        operation = (
+            "Select location, category, type, model, manufacturer, serial_number FROM Device "
+            "WHERE prefix = ?"
+        )
+    
+        cursor = self._database.cursor() 
+        cursor.execute(operation, (prefix.toUri(),))
+        result = cursor.fetchone() 
+        cursor.close()
+        # print result
+        if result == None:
+            return None
+        else:               
+            deviceProfile = DeviceProfile(prefix)
+            deviceProfile.setLocation(result[0])
+            deviceProfile.setCategory(result[1])
+            deviceProfile.setType(result[2])
+            deviceProfile.setModel(result[3])
+            deviceProfile.setManufacturer(result[4])
+            deviceProfile.setSerialNumber(result[5])
+        
+        return deviceProfile
+               
+    def getSeed(self, prefix):
+        """
+        get the seed of the specified device        
+        :param Name prefix: the device prefix
+        :return seed of the device if exists, otherwise return None
+        :rtype: HMACKey
+
+        """
+        operation = (
+            "Select seed_name, seed_sequence, seed_counter, seed FROM Device "
+            "WHERE prefix = ?"
+        )
+
+        cursor = self._database.cursor()
+        cursor.execute(operation, (prefix.toUri(),))
+        result = cursor.fetchone()
+        cursor.close()
+        #print result
+        if result == None:
+            return None
+        else:
+            seed = HMACKey(result[1], result[2], result[3], result[0]) 
+        return seed
+
+        # raise RuntimeError("getSeed is not implemented")
+
+    def getConfigurationToken(self, prefix):
+        """
+        get the seed of the specified device        
+        :param Name prefix: the device prefix
+        :return seed of the device if exists, otherwise return None
+        :rtype: HMACKey
+
+        """
+        operation = (
+            "Select configuration_token_sequence, configuration_token_counter, configuration_token FROM Device "
+            "WHERE prefix = ?"
+        )
+
+        cursor = self._database.cursor()
+        cursor.execute(operation, (prefix.toUri(),))
+        result = cursor.fetchone()
+        cursor.close()
+        #print result
+        if result == None:
+            return None
+        else:
+            configurationToken = HMACKey(result[0], result[1], result[2])
+        return configurationToken
+        # raise RuntimeError("getConfigurationToken is not implemented")
+
+    def getDeviceEntry(self, prefix):
+        """
+        get the specified device entry
+        :param Name prefix: the device prefix
+        :return '' return the corresponding row of the device
+        :rtype: str
+        """        
+        cursor = self._database.cursor()
+        cursor.execute("SELECT * FROM Device WHERE prefix =?", (prefix.toUri(),))
+        row = cursor.fetchone()
+        cursor.close()
+        return row
+
+    def deleteDevice(self, prefix):
+        """
+        delete specified device.
+        :param Name prefix: The device prefix
+        :return: 1 if successful, 0 if no device to delete, otherwise -1.
+        :rtype: INTEGER	
+        """
+        result = -1
+        if not self.doesDeviceExist(prefix):
+            return 0
+        cursor = self._database.cursor()
+        deleteDevice = "DELETE FROM Device WHERE prefix=?"
+        cursor.execute(deleteDevice, (prefix.toUri(),))
+        self._database.commit()
+        cursor.close()
+        return 1
+   
+    def getDeviceId(self, prefix):
+        """
+        get the device id of some specified device
+        :param Name prefix: the device prefix
+        :return id of the device, 0 if the device doesn't exist
+        :rtype: INTEGER
+        """
+        if not self.doesDeviceExist(prefix):
+            return 0
+        cursor = self._database.cursor()
+        operation = "SELECT id FROM Device WHERE prefix=?"
+        cursor.execute(operation, (prefix.toUri(),))
+        result = cursor.fetchone()
+        deviceId = result[0]
+        self._database.commit()
+        cursor.close()
+        return deviceId
+    
+    def updateDevice(self, prefix, newDeviceProfile = None , newSeed = None , newcConfigurationToken = None ):
+        """
+        update specifided device 
+        :param Name prefix 
+        :param DeviceProfile newDeviceProfile
+        :param HMACKey newSeed
+        :param newConfigurationToken
+        :return id of the device if successful, 0 if device not found, otherwise -1
+        :rtype int
+        """
+        raise RuntimeError("getConfigurationToken is not implemented")
+
+    def updateOneColumnOfDevice(self, prefix, columnName, newColumnValue):
+        """
+        update the value of a specified column of a specified device
+        :param Name prefix: the device prefix
+        :param str columnName: column to be updated 
+        :param newColumnValue: new column value
+        :return id of the device if successful. 0 if device not found, otherwise -1
+        :rtype int
+        """
+        result  = -1
+        if not self.doesDeviceExist(prefix):
+            return 0
+        
+        updateDevice = "UPDATE Device Set " + columnName + "=? WHERE prefix=?"
+        #print updateDevice       
+        cursor = self._database.cursor()
+        #print  newColumnValue
+        cursor.execute(updateDevice, (newColumnValue,prefix.toUri()))
+        self._database.commit()
+        result = cursor.lastrowid
+        cursor.close()
+        return result
+
+    def doesCommandExist(self, deviceId, commandName):
+        """
+        check if the specified command already exists.
+       
+        :param Integer device_id: the device id
+        :return True if the command exists, otherwise False
+        :rtype: bool
+        """
+        result = False
+
+        cursor = self._database.cursor()
+        cursor.execute("SELECT count(*) FROM Command WHERE device_id =? AND name = ?", (deviceId, commandName))
+        (count,) = cursor.fetchone()
+        if count > 0:
+            result = True
+        
+        cursor.close()
+        return result
+    
+    def addCommand(self, deviceId, name, commandToken):
+        """ 
+        Add a new command to the Command table, do nothing if the device already exists
+        
+        :param int deviceId: the device id to which the command belongs to
+        :param str name: the command name
+        :param HMACKey commandToken: the command token
+        :return the command id if it's added successfully, 0 if the command already exists, otherwise -1
+        :rtype: int
+        """
+        result = -1
+        data = (deviceId,
+               name,
+               commandToken.getName(),
+               commandToken.getSequence(),
+               commandToken.getCounter(),
+               commandToken.getKey()
+               )
+
+        #check if the command already exists, if yes return 0
+        if self.doesCommandExist(deviceId, name):
+            return 0
+
+        insertCommand = (
+            "INSERT INTO Command(device_id, name, command_token_name, command_token_sequence, command_token_counter, command_token)"
+            "VALUES(?,?,?,?,?,?)"
+        )
+        cursor = self._database.cursor()
+        cursor.execute(insertCommand, data)
+        self._database.commit()
+        result = cursor.lastrowid
+        cursor.close()
+        return result
+    
+    def deleteCommand(self, deviceId, name = None):
+        """
+        delete specified commands.
+        :param str name: The command name, if None, delete all commands of the device
+        :param int deviceId: device id of the command
+        :return: 1 if successful, 0 if no command to delete, otherwise -1.
+        :rtype: int
+        """
+        result = -1
+        if not name == None: 
+            if not self.doesCommandExist(deviceId, name):
+                return 0
+            cursor = self._database.cursor()
+            deleteCommand = "DELETE FROM Command WHERE device_id=? AND name=?"
+            cursor.execute(deleteCommand, (deviceId, name))
+            self._database.commit()
+            cursor.close()
+            return 1
+        else: 
+            selectOperation = "SELECT count(*) FROM Command WHERE deviceId=?"
+            cursor = self._database.cursor()
+            cursor.execute(selectOperation, (deviceId,))
+            (count,) = cursor.fetchone()
+            if not count > 0:
+                return 0
+            deleteCommand = "DELETE FROM Command WHERE deviceId=?"
+            cursor.execute(deleteCommand, (deviceId))
+            self._database.commit()
+            cursor.close()
+            return 1
+        
+        return result
+      
+    def getCommandsOfDevice(self, deviceId):
+        """
+        get all the commands of a specified device
+        :param int deviceId: device id of the command
+        :return command name list if any commands exist, otherwise None
+
+        """
+        operation = "SELECT name FROM Command WHERE device_id = ?"
+        #operation2 = "SELECT count(*) FROM Command WHERE device_id = ? "
+        cursor = self._database.cursor()
+        #cursor.execute(operation2,(deviceId,))
+        #(count,) = cursor.fetchone
+
+        #if not count > 0:
+            #return None
+        cursor.execute(operation, (deviceId,))
+        result = cursor.fetchall()                    
+        #print result
+        commandList = []
+        if result == None:
+           return commandList 
+        else:  
+           for row in result:
+               commandList.append(row[0]) 
+    
+        return commandList
+
+    def getCommandToken(self, deviceId, commandName):
+        """
+        get command token of a specified command 
+        :param int deviceId: device id of the command
+        :param str commandName: device name of the command
+        :return command token if command existsm, otherwise None
+        :rtype HMACKey
+        """
+        operation = "SELECT command_token_sequence, command_token_counter,command_token, command_token_name FROM Command WHERE device_id = ? AND name = ?"
+        cursor = self._database.cursor()
+        cursor.execute(operation, (deviceId, commandName))
+        result = cursor.fetchone()
+        if result == None:
+            return None
+        else:
+            commandToken = HMACKey(result[0], result[1], result[2], result[3])
+        return commandToken
+  
+    def doesServiceProfileExist(self, deviceId, serviceProfileName):
+        """
+        check if the specified service profile already exists.
+       
+        :param Integer device_id: the device id
+        :param str serviceProfileName: name of the service profile 
+        :return True if the service profile exists, otherwise False
+        :rtype: bool
+        """
+        result = False
+
+        cursor = self._database.cursor()
+        cursor.execute("SELECT count(*) FROM ServiceProfile WHERE device_id =? AND name = ?", (deviceId, serviceProfileName))
+        (count,) = cursor.fetchone()
+        if count > 0:
+            result = True
+
+        cursor.close()
+        return result
+
+    def addServiceProfile(self, deviceId, name):
+        """ 
+        Add a new command to the ServiceProfile table, do nothing if the device already exists
+        
+        :param int deviceId: the device id to which the command belongs to
+        :param str name: the service profile name
+        :return the service profile id if it's added successfully, 0 if the service profile already exists, otherwise -1
+        :rtype: int
+        """
+        result = -1
+        data = (deviceId,
+               name,
+               )
+
+        #check if the service profile already exists, if yes return 0
+        if self.doesServiceProfileExist(deviceId, name):
+            return 0
+
+        insertCommand = (
+            "INSERT INTO ServiceProfile(device_id, name)"
+            "VALUES(?,?)"
+        )
+        cursor = self._database.cursor()
+        cursor.execute(insertCommand, data)
+        self._database.commit()
+        result = cursor.lastrowid
+        cursor.close()
+        return result
+
+    def deleteServiceProfile(self, deviceId, name = None):
+        """
+        delete specified service profile.
+        :param str name: The command name, if None, delete all profiless of the device
+        :param int deviceId: device id 
+        :return: 1 if successful, 0 if no service profile to delete, otherwise -1.
+        :rtype: int
+        """
+        result = -1
+        if not name == None:
+            if not self.doesServiceProfileExist(deviceId, name):
+                return 0
+            cursor = self._database.cursor()
+            deleteProfile = "DELETE FROM ServiceProfile WHERE device_id=? AND name=?"
+            cursor.execute(deleteProfile, (deviceId, name))
+            self._database.commit()
+            cursor.close()
+            return 1
+        else:
+            selectOperation = "SELECT count(*) FROM ServiceProfile WHERE deviceId=?"
+            cursor = self._database.cursor()
+            cursor.execute(selectOperation, (deviceId,))
+            (count,) = cursor.fetchone()
+            if not count > 0:
+                return 0
+            deleteProfile = "DELETE FROM ServiceProfile WHERE deviceId=?"
+            cursor.execute(deleteProfile, (deviceId))
+            self._database.commit()
+            cursor.close()
+            return 1
+
+        return result
+
+    def getServiceProfilesOfDevice(self, deviceId):
+        """
+        get all the service profiles of a specified device
+        :param int deviceId: device id of the command
+        :return service profiles name list if any service profiles exist, otherwise None
+        """
+        operation = "SELECT name FROM ServiceProfile WHERE device_id = ?"
+        cursor = self._database.cursor()
+        cursor.execute(operation, (deviceId,))
+        result = cursor.fetchall()
+        #print result
+        serviceProfileList = []
+        if not result == None:
+            for row in result:
+                serviceProfileList.append(row[0])
+        return serviceProfileList
+
+