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ISSN: 2278 – 1323
International Journal of Advanced Research in Computer Engineering & Technology (IJARCET)
Volume 2, No 5, May 2013
1705
www.ijarcet.org

Abstract— These days Wireless Communication is one of the
popular areas of research. Mobile ad-hoc networks (MANET)
operate in the absence of any supporting infrastructure. The
absence of ﬁxed infrastructure in MANET makes it difﬁcult to
utilize the existing techniques for network services, and poses
number of various challenges in the area. The discovery and
maintenance of secure route is the most difficult challenge.
Security is one of the important issues in MANET. The
assumption of a trusted environment is not one that can be
realistically expected; hence, several efforts have been made
toward the design of a secure and robust routing protocol for ad
hoc networks. This paper includes study and overview of some
existing secure routing protocols in MANET.
Index Terms— AODV, DSDV, MANET, SRP,TORA.
I. INTRODUCTION
MANET is the collection of wireless mobile nodes forming
a temporary or short lived network without any base station.
The term routing is very important for a network. Routing is a
process of finding an efficient, reliable and secure path from a
source node to a destination node via intermediate nodes in a
network. Routing in MANET is a challenge due to dynamic
topology in network as mobile nodes can move in any
direction in the MANET. Instant network setup is the main
feature of MANET. MANET is useful in places that have no
communications infrastructure or when that infrastructure is
severely damaged. A small network for sharing resources can
be setup by mobile nodes (laptop, personal digital assistant,
smart phones).
MANETs employ wireless communication, where each node
participates as a source, destination, or intermediate router.
Ad hoc environments are attractive for military applications
and disaster response situations where fixed networking
infrastructures may not be available once damaged beyond
use. Protocol security is vital to proper operation. We
consider a protocol secure if it is accurate and reliable, even
when faced with malicious attackers.
In order for a MANET routing protocol to operate properly,
we must trust intermediate nodes that make up a routing path
will operate according to the protocol rules. If a malicious
.
Desai Piyusha P., M.E. Student, Computer engineering,
LDRP_ITR,Gandhinagar ,Gujarat Techincal University,.Surat,,Gujarat
,India.
host can inject itself into the routing path, proper routing
protocol operation is dependent on the attacker’s intentions.
Trusting intermediate nodes to follow protocol rules is a
significant issue in MANET implementations since these
networks are highly dynamic; nodes may continuously join
or leave the network and network connectivity changes with
mobility. Unfortunately, security is often an afterthought in
MANET protocol development. Security is commonly
ignored or designed in after the fact as vulnerabilities or
attacks are discovered. Moreover, the protocol’s upfront
security goals are commonly not addressed. Undefined
security goals complicate the security analysis task. It is
generally considered infeasible to analyze a protocol to
determine if it is vulnerable against unknown attacks.
There are several well known protocols in the literature that
have been specifically developed to cape with the limitations
imposed by ad hoc networking environments. Most of the
existing routing protocols follow two different design
approaches to confront the inherent characteristics of ad hoc
networks, named the table-driven and the source-initiated on
demand [5] approaches.
Fig. 1.1 Classification of Routing Protocals
II. SECURITY GOALS
For secure routing between two nodes, following security
goals should be satisfied.
(1) Confidentiality: Data in transit to be kept secret from
eavesdroppers.
A Study of Secure Routing in Mobile Ad-hoc
Networks
Desai Piyusha P.
Routing Protocols
Table
Driven Or
Proactive
Hybrid
DSDV WRS AODV DSR
Source on
Demand
Driven or
Reactive
ZRP TORA

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(2) Integrity: Data can not be modified without authorization.
Wireless networks inherently unreliable, so an adversary can
tamper with messages.
(3) Authentication: Communicating nodes need to verify
each others' identities. When node A sends data to node B,
how node B verify that data is send by mode A and not any
other node in the network.
(4) Availability: The service should be available all the time.
(5) Data Freshness: It suggests that the data is recent, and it
ensures that no old messages have been replayed.
(6) Non-repudiation: Sender and receiver cannot deny its
role in communication.
(7) Authorization: It ensures that only authorized nodes can
be accessed to network services or resources.
Instead of attempting to define common security goals based
on the multiple security views, it makes more sense to view
overall security in terms that determine if a protocol meets its
intended goals, even when faced with malicious intruders.
In order for a routing protocol to be effective it must deliver
an optimally correct route by possessing the following
properties:
• Accuracy. A routing protocol is accurate if it produces
routes that meet its objectives (i.e., the returned routes are
valid).
• Reliability. A routing protocol is reliable if its returned
routes are always accurate, even if non-malicious failures
(e.g., mobility, hardware failure, etc.) occur.
Accuracy and reliability must be maintained at all times for a
protocol to maintain its effectiveness.
III. ATTACKS ON MANET ROUTING PROTOCOLS
Attacks on mobile ad hoc networks can be classified into
following two categories:
A. Passive Attacks
A passive attack does not disrupt proper operation of the
network. The attacker snoops the data exchanged in the
network without altering it.. An attack which is specific to the
passive attack is given below:
1) Snooping
Snooping is unauthorized access to another person's data.
It is similar to eavesdropping but is not necessarily limited to
gaining access to data during its transmission..
B. Active Attacks
An active attack attempts to alter or destroy the data being
exchanged in the network, thereby disrupting the normal
functioning of the network.
Brief descriptions of active attacks are given below.
1) Network Layer Attacks
The list of different types of attacks are given below:
i) Wormhole Attack
In wormhole attack[1], a malicious node receives packets
at one location in the network and tunnels them to another
location in the network, where these packets are resent into
the network. This tunnel between two colluding attackers is
referred to as a wormhole. It could be established through
wired link between two colluding attackers or through a
single long-range wireless link. In this form of attack the
attacker may create a wormhole even for packets not
addressed to itself because of broadcast nature of the radio
channel.
ii) Black hole Attack
In Black hole attack[1], an attacker uses the routing
protocol to advertise itself as having the shortest path to the
node whose packets it wants to intercept. An attacker listen
the requests for routes in a flooding based protocol. When the
attacker receives a request for a route to the destination node,
it creates a reply consisting of an extremely short route. If the
malicious reply reaches the initiating node before the reply
from the actual node, a fake route gets created. Once the
malicious device has been able to insert itself between the
communicating nodes, it is able to do anything with the
packets passing between them. It can drop the packets
between them to perform a denial-of-service attack, or
alternatively use its place on the route as the first step in a
man-in-the-middle attack.
iii) Resource Consumption Attack
In this attack, an attacker tries to consume or waste away
resources of other nodes present in the network. The
resources that are targeted are battery power, bandwidth, and
computational power, which are only limitedly available in
ad hoc wireless networks.
iv) Routing Attacks
There are several attacks which can be mounted on the
routing protocols and may disrupt the proper operation of the
network. Such attacks are :
 Routing Table Overflow: In the case of routing table
overflow, the attacker creates routes to nonexistent
nodes. The main objective of such an attack is to
cause an overflow of the routing tables, which
would in turn prevent the creation of entries
corresponding to new routes to authorized nodes.
 Packet Replication: In the case of packet replication,
an attacker replicates stale packets. This consumes
additional bandwidth and battery power resources
available to the nodes and also causes unnecessary
confusion in the routing process.
2) Transport Layer Attacks
i) Session Hijacking
Session hijacking is a critical error and gives an
opportunity to the malicious node to behave as a legitimate
system. All the communications are authenticated only at the
beginning of session setup. The attacker may take the
advantage of this and commit session hijacking attack.
3) Application Layer Attacks
i) Repudiation: In simple terms, repudiation refers to
the denial or attempted denial by a node involved in a
communication of having participated in all or part of the
communication.
4) Multi-layer Attacks
Here we will discuss security attacks that cannot strictly be
associated with any specific layer in the network protocol
stack.
i) Denial of Service
In this, an attacker attempts to prevent legitimate and
authorized users from the services offered by the network.
One way is to flood packets to any centralized resource

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present in the network so that the resource is no longer
available to nodes in the network, as a result of which the
network no longer operating in the manner it was designed to
operate.
ii) Impersonation
In this attack, a compromised node may get access to the
network management system of the network and may start
changing the configuration of the system . A
man-in-the-middle attack is an example of impersonation
attack. The attacker reads and possibly modifies messages
between two end nodes without letting either of them know
that they have been attacked.
IV. RELATED WORK
Some of the secure routing protocols are discussed as follow:
A. Destination Sequence Distance Vector[7]
The Destination Sequence Distance Vector (DSDV) comes
under proactive or table driven routing protocol and is a well
known MANET routing protocol. Here each table must
contain the destination node address, the minimum number of
hops to that destination, the next hop in the direction of that
destination and an entry for sequence numbers for every
destination. A higher sequence number denotes a more recent
update sent out by the source node.
When a node receives any update information, it checks the
sequence number in the packet and if the information in the
packet is older than the receiving node has in its routing
tables, then the packet is rejected otherwise the information is
updated . After this the update packet is forwarded to all other
neighboring nodes except the one from which the packet
came.
B. Security Aware Ad-hoc Routing [5]
Security-Aware ad hoc Routing (SAR) makes use of security
attributes to take the routing decision. In SAR, security
metric is embedded into the RREQ packet. Nodes are
required to have keys for decryption of data while forwarding
or receiving the data. If a path with the required security
attributes is found a RREP is sent from an intermediate node
or the destination node to the source node. In case of more
than one route the shortest route is selected for data
forwarding.
C. Secure Ad hoc On-demand Distance Vector Routing
[2]
The SAODV (Secure Ad hoc On-demand Distance Vector
Routing) protocol [2] is an extension of AODV. Adversary
nodes may forge AODV packets, listen to others, reply
packets in their own interests, and report errors where there
are none. To defend these attacks, it is assumed that each
node has a certified public key. Hop-by-hop authentication is
used to protect routing messages, and all intermediate nodes
need to cryptographically validate the digital signatures
appended with a routing message.
D. Secure Routing Protocol (SRP) [3]
Secure Routing Protocol (SRP) is another routing protocol
which uses symmetric cryptography. The protocol is based
on route querying method. SRP Requires a Security
Association (SA) between source and destination node. Key
generated by the SA is used to encrypt and decrypt the data
by the two nodes.
A SRP Header (Figure 1) is added to the base header. The
RREQ packet consists of a query sequence number (QSEQ),
query identifier (QID), and the out put of a key hashed
function. The key hash function takes IP header, header of the
basic routing protocol, and the shared key.
The intermediate nodes broadcast the query to the
neighboring nodes and update their routing table. If receiving
node has the same QID in their routing table, query is
dropped. When the destination is reached, destination node
checks for the security metrics by calculating the key hash
function ―message authentication code (MAC)”. After
verifying the secret key it generates reply packet for source
node consisting of path from source to destination, QID,
QSEQ. After receiving the reply packet source node again
calculates its MAC. There can be multiple routes from source
to destination. Route maintenance in this protocol is also
done through route error message.
E. Secure AODV using RSA Signature[6]
An extension of the Ad Hoc On-demand Distance Vector
(AODV) [6] routing protocol has been proposed [7] to protect
the routing protocol messages. The Secure-AODV scheme
assumes that each node has certified public keys of all
network nodes, so that intermediate nodes can validate all
in-transit routing packets. The basic idea is that the originator
of a control message appends an RSA signature and the last
element of a hash chain (i.e., the result of n consecutive hash
calculations on a random number). As the message traverses
the network, intermediate nodes cryptographically validate
the signature and the hash value, generate the k-th element of
the hash chain, with k being the number of traversed hops,
and place it in the packet. The route replies are provided
either by the destination or intermediate nodes having an
active route to the sought destination, with the latter mode of
operation enabled by a different type of control packets.
The use of public-key cryptography imposes a high
processing overhead on the intermediate nodes and can be
considered unrealistic for a wide range of network instances.

ISSN: 2278 – 1323
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F. Temporary Ordered Routing Protocol [5]
The Temporally-Ordered Routing Algorithm (TORA) is for
routing data Mobile ad-hoc networks. The TORA attempts to
achieve a high degree of scalability . In its operation the
algorithm attempts to suppress, to the greatest extent
possible, the generation of far-reaching control message
propagation. The TORA does not use a shortest path solution,
an approach which is unusual for routing algorithms of this
type. TORA builds and maintains a Directed Acyclic Graph
rooted at a destination. No two nodes may have the same
height. Information may flow from nodes with higher heights
to nodes with lower heights. Information can therefore be
thought of as a fluid that may only flow downhill. By
maintaining a set of totally-ordered heights at all times,
TORA achieves loop-free multipath routing, as information
cannot 'flow uphill' and so cross back on itself.
The key design concept of TORA is localization of control
messages to a very small set of nodes near the occurrence of a
topological change. To accomplish this, nodes need to
maintain the routing information about adjacent (one hop)
nodes. The protocol performs three basic functions:
 Route creation
 Route maintenance
 Route erasure
V. CONCLUSION
This paper is an effort to concentrate on the overview study
of all routing protocols supporting security requirements
along with an overview of the various security goals and
major possible security attacks on routing process in mobile
ad hoc network. It has been further concluded that due to the
dynamically Changing topology and infrastructure less,
decentralized Characteristics, security and power awareness
is hard to achieve in mobile ad hoc networks.
REFERENCES
[1] Raj Tirthraj,Verma A K, “ Survey and Analysis of secure routing
protocols for MANETs,” in the proceeding of National Conference on
cutting Edge Computer and Electronics Technology (CECT 2009),
Pantnager, February14-16,pages501-06.
[2] M. G. Zapata, Secure Ad hoc On-Demand Distance Vector (SAODV)
Routing, Internet Draft: draft-guerrero-manetsaodv-00.txt, 2002.
[3] P. Papadimitratos, Z.J. Haas, P. Samar. The Secure Routing Protocol
(SRP) for Ad Hoc Networks. draft-papadimitratossecure-
routing-protocol-00.txt 2008-12-11.
[4] A K Verma, mayank Dave and R C Joshi, “Classification of Routing
Protocols in MANET”, at National Symposium on Emerging Trends in
Networking & Mobile Communication (NSNM-2003),pp. 132-139,
Sept 5-6, 2003. (dsdv aodv).
[5] Yu-Chee Tseng, Wen-Hua Liao, Shih-Lin Wu, “Mobile Ad Hoc
Networks and Routing Protocols”, Handbook of Wireless Networks
and Mobile Computing, Edited by Ivan Stojmenovic´ Copyright
©2002 John Wiley & Sons, Inc. ISBNs: 0-471- 41902-8 (Paper);
0-471- 22456-1 (Electronic).
[6] Manel Guerrero Zapata , and N. Asokan. Secure Ad hoc On-Demand
Distance Vector (SAODV) Routing. ACM Mobile Computing and
Communications Review, vol. 3, no. 6, July 2002, pp. 106-107.
[7] Perkins Charles E., Bhagwat Pravin: Highly Dynamic
Destination-Sequenced Distance-Vector Routing (DSDV) for Mobile
Computers, London England UK, SIGCOMM 94-8/94.
Piyusha Desai is a M.E. student in the Dept. of Computer Engineering,
LDRP_ITR, Gujarat Techinical University, Gujarat,India. She received his
B.E. degree in Computer Engineering from Veer Narmad South Gujarat
University, India in 2010. Her research interests include Mobile Ad-Hoc
Networks,Routing protocols in Manet.

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