A Lightweight Secure Time Synchronization
Mechanism for ISO/IEC/IEEE 21451 Sensor
Networks
Longhua Guo, Jun Wu, Jingwei Li, Jianhua Li
Shanghai Jiao Tong University
School of Electronic Information and Electrical Engineering
Shanghai, China
Email: junwuhn@sjtu.edu.cn
William J. Miller
MaCT
Maryland, United States
Abstract—In sensor network, ISO/IEC/IEEE 21451 standards
attach significance for its provided communication and
information models which facilitate the access of smart sensor to
a network. As a distributed system, many applications and
protocols in ISO/IEC/IEEE 21451 sensor network require
common clock through time synchronization. Ensuring the
security of time synchronization sets significant foundation to
basic communication. In this paper, we proposed a lightweight
secure time synchronization mechanism for ISO/IEC/IEEE 21451
sensor network which takes the security requirements including
authentication, integrity, confidentiality, nonrepudiation and
availability into consideration. Authentication phase, timestamp
transfer phase and synchronization phase comprise the main
steps for the time synchronization. Strong authentication
provides basis for security protection. Lightweight encryption
algorithm is utilized for more precise time synchronization.
Discussion and simulation result are given to support the
efficiency of the lightweight proposed secure time
synchronization.
Keywords—lightweight secure time synchronization;
ISO/IEC/IEEE 21451 Standard; sensor networks
I. INTRODUCTION
In the past few decades, sensor network which consists of
sensing, data processing and communication components has
developed rapidly and applied in many fields [1]. Currently,
the applications such as smart city, smart transportation and
environment monitoring have directly changes people’s daily
life. However, the barriers caused by different sensors’
protocols and standards have limited the rapid development of
sensor network. To address this issue, ISO/IEC/IEEE 21451
standards [2] provide the communication and information
models to facilitate the access of smart sensor to a network.
The standards support latest communication protocols such as
eXtensible Messaging and Presence Protocol (XMPP),
Hypertext Transfer Protocol (HTTP), Simple Network
Management Protocol (SNMP) and so on. Under the standard
specified in ISO/IEC/IEEE 21451, it is available for smart
sensors to communicate based on different latest
communication protocols.
As a distributed system, ISO/IEC/IEEE 21451 sensor
network tends to monitor and interact with physical change
timely. Due to the limitation of hardware clocks, local clocks
of the sensor nodes may differ from the system clock. However,
many applications and protocols require a common clock in
order to be available to particular or all nodes in some cases.
Time synchronization helps to adjust the local clocks into a
common timescale for nodes in the network. As a result, time
synchronization sets significant foundation to basic
communication for many applications in ISO/IEC/IEEE 21451
sensor network [3].
Usually deployed in an unattended even hostile
communication network, time synchronization protocols in
ISO/IEC/IEEE 21451 sensor network confront with evolving
cyber-attack and security threats [4]. The adversary may try to
change and interrupt valid synchronization messages or
distribute invalid synchronization using Denial-of-Service
(DoS) attack, the pulse-delay attacks, the wormhole attacks and
other new created cyber-attacks.
In the traditional secure time synchronization for sensor
network, many protocols are proposed to fight against the
cyber-attacks [5-8]. Two categories of secure time
synchronization include the abnormal detection based method
and the authentication based method [9]. The abnormal
detection based methods mainly focus on the identification of
invalid nodes and inconsistent synchronization message
through analyzing behaviors or neighbors and other principles.
The authentication based methods mainly utilize shared
pairwise key to authenticate the synchronization messages [10].
However, they all introduced high communication overhead
and can’t be used in the ISO/IEC/IEEE 21451 sensor network
directly. Secure time synchronization of communication in
ISO/IEC/IEEE 21451 sensor network is still an important issue
deserving research.
In this paper, a lightweight secure time synchronization
mechanism is proposed for ISO/IEC/IEEE 21451 sensor
networks. The main parts consist of authentication phase,
timestamp transfer phase and synchronization phase. In the
authentication phase, mutual authentication between sensor
nodes and application is achieved. Afterwards, the timestamp
information is transferred with lightweight encryption
algorithm. According to the received timestamp, the time is
synchronized with adjustment. The remainder of the paper is
organized as follows. Section II describes the background