Proc. SPIE. 6982, Mobile Multimedia/Image Processing, Security, and Applications 2008
KEYWORDS: Mobile devices, Data transmission, Computer simulations, Cryptography, Wireless communications, Information security, Computer security, Device simulation, Mobile communications, Network security
Existing Ad Hoc routing protocols are mostly based on efficiency-driven protocols. Malicious nodes can easily impair
the performance of wireless ad hoc networks as a result of different actions such as packet dropping or black hole attacks
without being detected. It is virtually impossible to find out these kinds of malicious before they attack, therefore it
would be sensible to base detection of malicious nodes on post route discovery stage, i.e. when packets are transmitted
on discovered routes. In this paper we shall review existing techniques for secure routing and propose to use credibility
based route finding protocols. Each node would monitor its neighbors' pattern of delivering packets and regularly update
their "credibility" according to certain criteria. The level of trust in any route will be based on the credits associated with
the neighbor belonging to the discovered route. We shall evaluate the performance of the proposed scheme by modifying
our simulation system so that each node has a dynamic changing "credit list" for its neighbors' behavior. We shall
conduct a series of simulations with and without the proposed scheme and compare the results. We will demonstrate that
the proposed mechanism is capable of isolating malicious nodes and thereby counteracting black hole attacks. We will
discuss problems we encountered and our solutions. We would also further develop the protocol, to investigate the
possibility of using the unique prime factorization theory to enable nodes acquiring more trust knowledge beyond its
immediate neighborhood. Such an approach helps to further secure route-finding procedures.
Malicious nodes can seriously impair the performance of wireless ad hoc networks as a result of different actions
such as packet dropping. Secure routes are shortest paths on which every node on the route is trusted
even if unknown. Secure route discovery requires the adoption of mechanisms of associating trust to nodes. Most
existing secure route discovery mechanisms rely on shared keys and digital signature. In the absence of central
nodes that act as certification authority, such protocols suffer from heavy computational burden and are vulnerable
to malicious attacks. In this paper we shall review existing techniques for secure routing and propose to
complement route finding with creditability scores. Each node would have a credit list for its neighbors. Each node
monitors its neighbors' pattern of delivering packets and regularly credits are reviewed and updated accordingly.
Unlike most existing schemes the focus of our work is based on post route discovery stage, i.e. when packets are
transmitted on discovered routes. The level of trust in any route will be based on the credits associated with the
neighbors belonging to the discovered route. We shall evaluate the performance of the proposed scheme by
modifying our simulation system so that each node has a dynamic changing "credit list" for its neighbors'
behavior. We shall conduct a series of simulations with and without the proposed scheme and compare the results.
We will demonstrate that the proposed mechanism is capable of isolating malicious nodes and thereby
counteracting black hole attacks.
For secure mobile wireless networks whose topologies are changed dynamically in insecure environments, mobile users
need to keep in contact with each other for the purpose of user authentications. For instance, the network formed by a
group of soldiers equipped with wireless devices in a battlefield. Maintaining a high connectivity is crucial in such
networks in order to authenticate scattered individuals and to be able to communicate with each other. To establish
connections, different mobile ad hoc network routing protocols have been developed. However, much research has
shown that these protocols are incapable of maintaining high connectivity when the node density is lower in the
network. This paper proposes a mechanism to enhance the node connectivity, which is specifically effective for mobile
ad hoc networks with lower node densities. It selects some nodes with larger transmission power as strategic nodes to
assist in establishing connections with remote nodes, which are unable to connect with otherwise. The strategic nodes
have the ability to connect with each other. Whenever a remote mobile node has a request to connect to another remote
mobile node, the strategic nodes function as normal mobile nodes and may forward the connection requests to the
desired remote destination node. The mechanism is simulated in different scenarios with various node densities, and the
results show that the node connectivity is generally enhanced with the benefit of lower node density network, gaining
Wireless ad hoc networking offers convenient infrastructureless communication over the shared wireless channel. However, the nature of ad hoc networks makes them vulnerable to security attacks. Unlike their wired counterpart, infrastructureless ad hoc networks do not have a clear line of defense, their topology is dynamically changing, and every mobile node can receive messages from its neighbors and can be contacted by all other nodes in its neighborhood. This poses a great danger to network security if some nodes behave in a malicious manner. The immediate concern about the security in this type of networks is how to protect the network and the individual mobile nodes against malicious act of rogue nodes from within the network. This paper is concerned with security aspects of wireless ad hoc networks. We shall present results of simulation experiments on ad hoc network's performance in the presence of malicious nodes. We shall investigate two types of attacks and the consequences will be simulated and quantified in terms of loss of packets and other factors. The results show that network performance, in terms of successful packet delivery ratios, significantly deteriorates when malicious nodes act according to the defined misbehaving characteristics.