TinySeRSync: Secure and Resilient Time Synchronization for Wireless Sensor Networks
Released on 09/28/06.
TinySeRSync is a software package providing both secure single-hop pair-wise time synchronization and secure and resilient global timesynchronization on MICAz motes running TinyOS. The secure single-hop pair-wise time synchronization protocol uses hardware-assisted, authenticated medium access control (MAC) layer timestamping. Unlike the previous attempts, this technique can handle high data rate in MICAz motes (in contrast to the low data rate in MICA2 motes).
The secure and resilient global time synchronization technique is based on a novel use of the µTESLA  broadcast authentication protocol for local authenticated broadcast. We solved the conflict between the goal of achieving time synchronization with µTESLA-based broadcast authentication and the fact that µTESLA requires loose time synchronization.The resulting protocol is secure against external attacks and resilient against compromised nodes.
Details about TinySeRSync can be found in .
For questions please contact Peng Ning at pning (at) ncsu.edu.
How to Use
A Glimpse of the Performance
Secure Single-Hop Pair-Wise Time Synchronization
We tested 30 pairs of nodes in our lab to obtain the synchronization
precision. For each pair of nodes, we ran 500 rounds of pairwise time
synchronization. After two nodes finish a pairwise time
synchronization, a third reference node broadcasts a query to them.
Each of the node records the MAC layer receiving time of the broadcast
message and sends the receiving time to the reference node. This
allows the reference node to calculate the synchronization error. The following figure shows the distribution of the
pairwise synchronization error. Note that each tick is 8.68 µs.
Secure and Resilient Global Time Synchronization
We tested the secure and resilient global time synchronization in a test-bed consisting of 60 MICAz motes. The topology of the network is shown in figure below. (To emulate a multi-hop network in a limited space, we hard coded the neighbor relation in the experiment code. However, the code for neighbor discovery is available in TinySeRSync.) Node 1 (with the solid circle) is configured as
the source node.The different node shapes represent nodes deployed
at different times during incremental deployment. At the
beginning of the experiment, we deployed the 49 nodes marked as
circles. We then added 5 new nodes into the network about 10 minutes
later, and added another 6 new nodes about 1 minute later.
experiment, we set tolerance t=2 (each node can tolerate up to 2 colluding malicious neighbor nodes), and the global synchronization interval is
set to 10 s. The nex figure shows the history of the
average synchronization error and the coverage in this experiment. The left Y-axis shows the Average Synchronization Error (Left Y-axis), and the right Y-axis shows the Coverage. As
shown in the figure, when new nodes were just added into the network,
they could not be synchronized immediately, and the average
synchronization error was large and the synchronization rate dropped
to around 90%. However, after a few rounds of global
synchronization, all these new nodes were correctly synchronized,
resulting in a low average synchronization error and 100%
Copyright and Disclaimer
All code modified from the TinyOS distribution or other sources are copyright protected following their original copyright policies. See the copyright notice included in those files.
All new code in (the files added in) this distribution is Copyright 2006 by North
Carolina State University. All rights reserved. Redistribution and use
in source and binary forms are permitted provided that this entire
copyright notice is duplicated in all such copies, and that any
documentation, announcements, and other materials related to such
distribution and use acknowledge that the software was developed at
North Carolina State University, Raleigh, NC. No charge may be made
for copies, derivations, or distributions of this material without the
express written consent of the copyright holder. Neither the name of
the University nor the name of the author may be used to endorse or
promote products derived from this material without specific prior
IN NO EVENT SHALL THE NORTH CAROLINA STATE UNIVERSITY BE LIABLE TO
ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION,
EVEN IF THE NORTH CAROLINA STATE UNIVERSITY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE NORTH CAROLINA STATE UNIVERSITY HAS
NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
 Kun Sun, Peng Ning, Cliff Wang, An Liu, Yuzheng Zhou, "TinySeRSync: Secure and Resilient Time Synchronization in Wireless Sensor Networks'', in Proceedings of the 13th ACM Conference on Computer and Communications Security (CCS'06), Alexandria, VA, November 2006.
 A. Perrig, R. Szewczyk, V. Wen, D.Culler, and D. Tygar, "SPINS: Security Protocols for Sensor Networks". In Proceedings of Seven Annual International Conference on Mobile Computing and Networks, pages 521-534, July 2001.
This material is based upon work supported by the National Science Foundation (NSF) under Grant CAREER-0447761. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF.