Key Dependent Cipher Scheme
for Sensor Networks
Hassan Noura
∗
, Steven Martin
∗
, Khaldoun Al Agha
∗
and Walter Grote
†
∗
LRI, Universit´ e Paris-Sud / CNRS, Paris, France
†
Universidad Tecnica Federico Santa Maria, Valparaiso, Chile
{noura, smartin, alagha}@lri.fr, walter.grote@usm.cl
Abstract—Wireless Sensor Networks (WSN) are a promising
future for many commercial and military applications. WSN is
vulnerable to a variety of potential attacks (active and passive).
The confidentiality of WSN is an essential service and becoming a
major concern for security WSN protocol designers. However, the
characteristics of WSN (limitations of power, computation and
memory) impose security challenges, since the conventional ci-
phers suffer from these limitations. In this paper, a new different
cipher technique is defined to ensure the data confidentiality with
a significant reduction of computational complexity, energy cost,
and communication overhead. The proposed cipher is applied on
a set of packets called generation. The strength of the proposed
cipher against attacks is based on its dynamic property. The basic
scheme was tested and evaluated by comparing it with Advanced
Encryption Standard (AES) algorithm, which is considered as a
reliable and robust cipher algorithm. Theoretical and simulation
results of the proposed cipher scheme show that it is immune
against linear, differential, chosen/known-plain-text, brute force,
and statistical attacks.
I. I NTRODUCTION
WSN is nowadays deployed in a different set of applications
such as smart houses, buildings, battlefield, environmental
monitoring, .etc. The sensor nodes build a network topology
by connecting them with their sensor vicinity. Many WSN
is actually presented as ZigBee [1], WirlessHART [2], .etc,
which realize the communication among nodes by a multi-hop
routing protocol. The WSN user is divided into two different
types: (i) a sensor node that generates and transmits stream
data corresponding to a specific querier (e.g., information
about moving objects) and (ii) a querier (a laboratory, a
corporate organization, etc.) that poses queries on the sensor
readings, and periodically receives stream data from the sink
(sensor node). The problem of sensor mode exists in the rapid
depletion of its battery, which terminates consequently the
lifespan of corresponding network. In addition to common
network threats, WSN is susceptible to several attacks and
is not as easy to prevent it. Many countermeasures have
been developed and introduced to strengthen WSN against
attacks. The security in WSN is becoming a principal issue
for researchers and industry, since without it, sensitive data
will be accessible by adversaries such as hospital and military
applications. Two kinds of attacks can be performed: active
and passive. The passive and active attacks can damage the
confidentiality of the network and its authentication respec-
tively. It is rather difficult to detect the passive attacks com-
pared to the active ones, since passive ones aim to know their
contents in secret manner. The essential security services that
must be ensured to attain secure WSN are: data confidentiality,
integrity, source authentication and control access. To ensure
the data confidentiality, the conventional technique used to
solve the passive attack problems is by encrypting packets
between the sink and the received nodes using symmetric
key cipher like the Advanced Encryption Standard (AES) [3],
Which is robust against attacks, but requires high computation
complexity and consequently an expensive energy cost. Many
modification security mechanisms have been adapted to pro-
vide data confidentiality for WSN such as [4], [5], [6], [7].
However, when each one is performed, a high degree of
security should be achievable, but takes into consideration
the computation, communication limitations of WSN, there is
always a trade-off between security and performance. Hence,
the limitations of WSN prevent an efficient implementation
of these scenarios. The WSN limitations force us to design
a robust cipher scheme with a low computational complexity
according to the available resource constraints. In the form
of a security cipher scheme, three contributions can be made
to reduce the complexity and solve the above challenges
(i) to apply it on the level of packets ; (ii) the use of
invertible, flexible and key dependent cipher to reduce the
round iterations to one; (iii) to employ a dynamic diffusion
layer using a simple algebraic model as a cipher scheme;
(iv) robustness of the proposed cipher is due to the use of
the dynamic key. In addition, a new header is introduced
for each packet with 4 bytes length, which is used in the
key derivation function to provide the deterministic property.
This paper ensures data confidentiality with a minimum trade-
off between security and performances, while a new kind of
cipher scheme is designed to work with limited resources and
reduce the computation complexity. The ultimate objective is
to realize a cipher scheme that can ensure a safe transmission
with a remarkable efficiency. The rest of this paper is organized
as follows: Section II describes the standard tools such the
symmetric cipher AES, then it summarizes the state of the
art of recent security WSN protocols. Section III describes
the proposed secure scheme that consists on a new diffusion
layer. Performance and security analysis of the proposed cipher
are analyzed in section IV. Finally, section V presents our
conclusion.
978-1-4799-1004-5/13/$31.00 ©2013 IEEE
2013 12th Annual Mediterranean Ad Hoc Networking Workshop (MED-HOC-NET)
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