SECURING UNDERWATER WIRELESS

COMMUNICATIONNETWORKS

ABSTRACT

Underwater wireless communication networks (UWCNs) are particularly vulnerable to malicious attacks due to the high bit error rates, large and variable propagation delays and low bandwidth of acoustic channels in water.

The unique characteristics of the underwater acoustic channel and the differences between such networks and their ground based counterparts require the development of efficient and reliable security mechanisms.

The different attacks possible are Jamming, Wormholes, Selective Forwarding, Sybil Attacks, etc.

Research challenges are open for secure localization, routing and time synchronization.

AGENDA

Underwater wireless communication networksCharacteristics and vulnerabilities of UWCNsAttacks on UWCNs and counter measuresSecurity RequirementsResearch ChallengesSummaryApplications Conclusion

UNDERWATER WIRELESS COMMUNICATION NETWORKS

UWCNs include sensors and autonomous underwater vehicles (AUVs).

Each sensor node is a small, energy constrained device with the ability to sense the surrounding environment.

The AUV has high mobility, deployed for applications that need mobility.

The sink (base station) behaves as an interface between the sensor nodes and the clients.

Underwater sensor network with AUVs

COMMON TERMINOLOGIES

AttackAttacker, Intruder, AdversaryVulnerabilityThreat Defence

CHARACTERISTICS OF UWCNs

Radio waves do not propagate well underwater due to high energy absorption of water.

Acoustic channels have low bandwidth and are severely affected by multipath, fading, and the refractive properties of the sound channel.

Since underwater hardware is more expensive, underwater sensors are sparsely deployed.

More stringent power requirements since acoustic communications are more power-hungry.

VULNERABILITIES OF UWCNs

High bit error rates cause packet errors.Eavesdropping may occur.Malicious nodes can create out-of-band

connections, referred to as wormholes. The dynamic topology of underwater sensor network not only facilitates the creation of wormholes but it also complicates their detection.  

Since power consumption is higher and underwater sensors are sparsely deployed, energy exhaustion attacks to drain the batteries of the nodes pose a serious threat for the network lifetime.

ATTACKS ON UWCNS AND COUNTERMEASURES

The different attacks possible are:JammingWormhole AttackSinkhole AttackHELLO Flood AttackAcknowledgement SpoofingSelective ForwardingSybil Attack

Jamming

A jamming attack consists of interfering with the physical channel by putting up carriers on the frequencies used by nodes to communicate.

To avoid Jamming…….

Spread spectrum is the most common defence. The common techniques are Frequency hopping spread spectrum (FHSS) and Direct hopping spread spectrum (DHSS).

In-network knowledge of the extent of the jammed region may also allow for automatic routing avoidance or mobile jammer tracking.

If jamming cannot be prevented, it may instead be detected and mapped by surrounding nodes.

Wormhole attackA wormhole is an out-of-band connection

created by the adversary between two physical locations in a network with lower delay and higher bandwidth than ordinary connections.

Technique to handle Wormhole Attack….A distributed mechanism named Distributed Visualization of

Wormhole (Dis-VoW) can be used to detect wormhole attacks.

Sybil Attack

An attacker with multiple identities can pretend to be in many places at once.

Since identity fraud is central to the Sybil attack, proper authentication is a key defence.

Another defence is location verification.

Other Attacks

Sinkhole AttackHere, a malicious node attempts to attract traffic from a

particular area towards it.Geographic routing and authentication of nodes

exchanging routing information are possible defences against this attack.

HELLO Flood Attack A node receiving a HELLO packet from a malicious node

may interpret that the adversary is a neighbour; this assumption is false if the adversary uses high power for transmission.

Bidirectional link verification can help protect against this attack. Authentication is also a possible defence.

Acknowledgement Spoofing A malicious node overhearing packets sent

to neighbour nodes can use this information to spoof link layer acknowledgments with the objective of reinforcing the weak link or a link located in a shadow zone.

A solution to this attack would be encryption of all packets sent through the network.

Selective Forwarding Malicious nodes drop certain messages

instead of forwarding them to hinder routing. Multipath routing and authentication can be

used to counter this attack.

SECURITY REQUIREMENT

AuthenticationConfidentialityIntegrityAvailability

RESEARCH CHALLENGES

The security issues and open challenges for 1. Secure time synchronization2. Secure localization 3. Secure Routing

Secure Time Synchronization

Time synchronization is essential in many underwater applications such as synchronized sensing tasks.

The open research issues are:1. Because of high and variable propagation

delays of UWCNs, the time required to synchronize nodes should be investigated.

2. Efficient and secure time synchronization schemes with small computation and communication costs need to be designed to defend against delay and wormhole attacks.

  Secure Localization

Localization is a very important issue for data tagging. It can also help in making routing decisions.

Localization schemes can be classified into: 1. Range-based schemes (i) Anchor-based schemes (ii) Distributed positioning schemes 2. Range-free schemes

  The open research issues…..

Effective cryptographic techniques are required to prevent injection of  false information in UWCNs. 

Algorithms able to determine the location of sensors even in the presence of Sybil and wormhole attacks have to be developed.

Techniques to identify malicious or compromised anchor nodes and to avoid false detection of these nodes are required.

Secure localization mechanisms able to handle node mobility in UWCNs need to be devised.

Secure Routing

Routing is specially challenging in UWCNs due to the large propagation delays, the low bandwidth, the effort of battery refills of underwater sensors, and the dynamic topologies.

Therefore, routing protocols should be designed to be energy-aware, robust, scalable and adaptive.

Spoofing, replaying or altering the routing information affects routing.

The open research issues are……

There is a need to develop reputation-based schemes that analyse the behaviour of neighbours and reject routing paths containing nodes that do not cooperate in routing.

Quick and powerful encryption and authentication mechanisms against outside intruders should be devised for UWCNs.

Sophisticated mechanisms should be developed against insider attacks such as selective forwarding, Sybil attacks and HELLO flood attacks.

There is a need to develop new techniques against wormholes and sinkholes, and improve existing ones.

ADVANTAGES OF UWCNs

It avoids data spoofing.

It avoids privacy leakage.

It minimizes communication and computational cost.

Maximizes the battery power by preserving the power of the sensors.

DRAWBACKS

Routing is specially challenging in UWCNs due to the large propagation delays, the low bandwidth, the effort of battery refills of underwater sensors, and the dynamic topologies.

Schemes are challenging as they do not work well in mobile environments.

APPLICATIONS

Coastal Surveillance systems

Search and rescue operations

Oceanographic studies

Marine Archaeology

CONCLUSION

As UWCNs have huge scope of applications in sensitive military and intelligence fields, security of the network is of paramount importance.

This report gives an overall view of the unique characteristics of UWCNs, some of the common threats and attacks faced by such a network and some solutions to overcome these problems.

The main research challenges related to secure time synchronization, localization and routing have also been surveyed.

REFERENCES1. Mari Carmen Domingo, “Securing Underwater

Wireless Communication Networks”, IEEE Wireless Communications, February 2011.

2. Zaihan Jiang, “Underwater Acoustic Networks – Issues and Solutions”, International Journal of Intelligent Control And Systems, Vol. 13, No. 3, Page No. 152-161, September 2008.

3. Weichao Wang, Jiejun Kong, Bharat Bhargava, Mario Gerla, “Visualisation of Wormholes in Underwater Sensor Networks: A Distributed Approach”, Int. J. Security and Networks, Vol. 3, No. 1, Page No. 10-23, 2008. 

4. Milica Stojanovic (Massachusetts Institute of Technology), “Underwater Wireless Communications: Current Achievements and Research Challenges”, IEEE newsletter, 2006.

5. “Underwater Acoustic Sensor Networks (UW-ASN)”, Broadband and Wireless Networking Laboratories.