phani-final123 (3)

“A Routing-Driven Public-Key Cryptosystem Based Key Management Scheme for A Sensor Network”

INTRODUCTION

1.1 Purpose of the project:

This project proposes a novel routing-driven RSA algorithm based key management

scheme for a sensor network. This establishes shared keys only for those neighboring

sensors that communicate with each other rather establishing shared keys for all pairs of

neighboring sensors .This project also proposed how user authentication and session key

verification can be done in a single step process at the receiving end.

1.2 Motivation:

As the wireless technologies has become the need of an hour, Securing sensor networks

has received much attention in the last few years and as so many research works are

going on in order to achieve stronger security and to reduce overhead to the maximum

possible extent on wireless networks created a strong interest in me to do some work

concerning security issues on wireless sensor networks.

1.3 Existing Techniques:

Previous research on sensor network security mainly considers homogeneous

sensor networks [1],[2]and [4], where all sensor nodes have the same capabilities.

An Existing key management schemes require a large storage space for key pre-

distribution [4] and are not suitable for small sensor nodes.

Most existing key management schemes try to establish shared keys for all pairs

of neighbor sensors, no matter whether these nodes communicate with each other

or not, and this causes large overhead.

Sensor key management schemes are designed to set up shared keys for all pairs

of neighbor sensors, without considering the actual communication pattern.

Dept. of P.G Studies,VTU Belgaum Page 1


1.3.1 Disadvantage of an existing system:

Homogeneous ad hoc networks have poor performance and scalability.

It needs a large storage space [4].

1.4 Related Work:

Many key management schemes have been investigated in literatures. Random key pre-

distribution scheme [1] was first proposed by Eschenauer and Gligor. The basic idea of

their scheme was randomly selecting a subset of communication keys from a very large

size key pool, and storing into each sensor’s memory before deployment.

Chan et al presented q-composite scheme[21] which required two neighbor nodes share

at least q (q>1) common keys to establish a secure link.

Du et al. and Liu et al extended the basic random key pre-distribution scheme to pair

wise key pre-distribution scheme. In their scheme[21], the resilience against node capture

was significantly improved.

Liu et al. presented pair-wise key establishment scheme using pre-deployment

knowledge and Rabin’s scheme to achieve high degree of connectivity and strong

resilience against nodes capture [22]. In this, an effective pair-wise key establishment

scheme was implemented based on Rabin’s scheme without the knowledge of pre-

deployment. He proposed a framework for key management schemes in distributed

wireless sensor networks with heterogeneous sensor nodes.



1.5 Proposed Work:

The proposed key management scheme is implemented in a sensor network (SN)

model for better performance and security.

A public key algorithm–RSA is used to further improve the key management

scheme.

This project proposed a routing-driven key management scheme, which

establishes shared keys only for those neighboring sensors that communicate with

each other by using RSA public-key algorithm along with Quantum Key

Distribution Protocols (QKDPs).



LITERATURE SURVEY

The following works were carried out by specific persons in the area of wireless sensor

networks:

L. Eschenauer and V.D.Gligor, “A key management scheme for distributed sensor

networks”-(2002)

In this paper, a Dynamic Combinatorial Key management scheme(DCK) was

implemented to provide efficient, scalable, and survivable dynamic keying in a clustered

sensor network with a large number of sensor nodes[1]. DCK employs the Exclusion-

Basis Systems (EBS) as the underlying framework for key management at both the

cluster and the sensor node levels. DCK enhances network security by localizing cluster

key management functions, thus limiting the impact of sensor node capture to the

attacked cluster.DCK is efficient in terms of energy consumption and storage. Also, it

significantly outperforms other dynamic keying schemes, in particular with regards to

energy consumed in key refreshment and re-keying after node capture.

Drawbacks: This model includes regarding clustered (homogeneous) networks only.

And also using of DCK limits the impact of sensor nodes to the attacked cluster but not

completely eliminated.

H. Chan, A. Perrig, and D. Song, “Random key pre-distribution schemes for sensor

networks”-(2003)

They presented three new mechanisms for key establishment using the framework of pre-

distributing a random set of keys to each node because asymmetric key cryptosystems are

unsuitable for use in resource constrained sensor nodes and the nodes could be physically

compromised by an adversary [2]. First, in the q-composite keys scheme, they trade off

the unlikeliest of a large-scale network attack in order to significantly strengthen random

key pre-distribution's strength against smaller-scale attacks. Second, in the multipath-



reinforcement scheme, they showed how to strengthen the security between any two

nodes by leveraging the security of other links. Finally, the random-pair wise keys

scheme, which perfectly preserves the secrecy of the rest of the network when any node

is captured, and also enables node-to-node authentication.

Drawbacks: This model only suits well for homogeneous sensor networks and

unsuitable for heterogeneous wireless sensor networks where the sensors will have

different capabilities.

David J. Malan, “Toward PKI for Sensor Networks”-(2004)

He made implementations on the evaluation of elliptic curve cryptography (ECC) with

163-bit keys, which ultimately reduce space for distribution of keys[3].

Drawbacks: Here, as this method depends on curves, the computation of product modulo

is very difficult.

Arjan Durresi, Vijay Bulusu, Vamsi Paruchuri, Mimoza Durresi, Raj Jain, “Key

Distribution in Mobile Heterogeneous Sensor Networks”-(2006)

In this paper, two schemes were proposed namely; key pre-distribution using separate

key pool and key pre-distribution using segmented key pool. They allow the mobile

nodes to interact with the stationary nodes of different networks [4]. In key pre-

distribution with separate key pool, a separate key pool was used to connect the mobile

nodes to the stationary nodes. In key pre-distribution with segmented key pools, a large

key pool was divided into disjoint segments and each of these segments was assigned to a

different sensor network.

Drawbacks: As this method requires generation of more keys for the purpose of pre-

distribution, there is wastage of more space and energy for pre-distribution of key polls

among different networks.



Jeremy Brown, Xiaojiang Du, Kendall Nygard, “An Efficient Public-Key-Based

Heterogeneous Sensor Network Key Distribution Scheme”-(2007)

An idea of key-distribution scheme for a heterogeneous sensor network was described in

this paper. The scheme can guarantee that arbitrary nodes will be able to connect with

each other, and all messages are cryptographically secure. This scheme provides facilities

for in-network processing, which will help in optimizing usage of sensor resources [5].

Compromised nodes do not affect other parts of the sensor network. All of the damage is

localized to the node’s immediate neighbors, and provided that the compromise is

detected, the security breach was fairly stopped.

Drawbacks: Public-key-Based key management scheme doesn’t guarantees the detection

of presence of any third party (eavesdroppers).

Yong Ma, Siddharth Dala1, Majd Alwan, James Aylor, “ROP: A Resource Oriented

Protocol for Heterogeneous Sensor Networks”-(2007)

They described a network model that was adaptively formed according to the resources

of its members. A protocol named Resource Oriented Protocol (ROP) was developed to

create the network model [6]. This protocol entails two phases: topology formation and

topology update. In the first topology formation phase, sensors report their characteristics

of available resources, and then local cluster heads aggregate these reports and send to

sensors with largest resource capacity (LRC). After this step, based on the reports, LRCs

decide the topology and appoint cluster heads from top to bottom levels. In the topology

update phase, sensors maintain their route cache reactively. They also pointed ROP that

energy efficiency cannot always result in longer system lifetime especially in

heterogeneous networks. Instead, balancing resources among sensors and saving energy

for those more resource-constrained sensors are greatly helpful in lengthening the overall

system lifetime architecture. The targeted areas of applications include tele-health



applications, health care facilities and other care settings, in addition to more secure

automation applications.

Drawbacks: Here, the simulation, emulation and deployment process of the proposed

protocol is difficult.

Venkata Krishna Ravi, Bo Sun, Xiaojiang Du, Fei Hu, Michael Galloway, Yang

Xiao, “A survey of key management schemes in wireless sensor networks”-(2007)

Sensor nodes used to form Wireless sensor networks are resource-constrained, which

make security applications a challenging problem. Efficient key distribution and

management mechanisms are needed besides lightweight ciphers [7]. Many key

establishment techniques have been designed to address the tradeoff between limited

memory and security, but which scheme is the most effective is still debatable. They

provided a survey of key management schemes in wireless sensor networks.

Drawbacks: They noticed that no key distribution technique is ideal to all the scenarios

where sensor networks are used; therefore the techniques employed must depend upon

the requirements of target applications and resources of each individual sensor network.

Xiaojiang Du, Hsiao-Hwa Chen, Yang Xiao, Mohsen Guizani, “A Pseudo-Random

Function Based Key Management Scheme for Heterogeneous Sensor Networks”-(2007)

They presented an efficient Pseudo Random Function based key management scheme for

heterogeneous sensor networks[8]. The PRF-based scheme consists of three phases: key

pre-distribution; shared-key discovery; and establishing pair-wise key by a H-sensor.

They also presented a centralized and a distributed shared-key discovery scheme, and

compare their communication overheads. In the PRF based scheme, powerful H-sensors

are utilized to provide efficient and effective key establishment for neighbor L-sensors.



The performance evaluation and security analysis showed that the PRF-based key

management scheme can significantly reduce the storage requirement in achieving better

security than several other key management schemes.

Drawbacks: Not enough control of key ring size: it is possible that applying the formula

to sensor id and key in a key pool will yield key ring that is;

too large - larger than sensor memory

too small – not enough for the network to be connected

In either case node id should be regenerated

Sk. Md. Mizanur Rahman, Nidal Nasser, Kassem Saleh, “Identity and Pairing-based

Secure Key Management Scheme for Heterogeneous Sensor Networks”-(2008)

Key management poses a main concern for security operation in sensor

network[10]. Most existing key management schemes try to establish shared

keys for all pairs of neighbor sensors, no matter whether these nodes

communicate with each other or not, and causes large overhead. Recent trend of

research mainly consider homogeneous sensor network and a few consider

heterogeneous sensor network for key management. They considered heterogeneous

sensor network (HSN) as a model for their proposed novel key agreement protocol

based on pairing identity based encryption (IBE). The proposed scheme reduces

the key spaces of the nodes, in fact nodes do not need to store any key of the other nodes

rather it computes secret sharing key by using pairing and IBE properties. Security

analysis shows it also robust against different attacks such as replay attack,

masquerade attack, and integrity attack.

Drawbacks: This network model requires specific requirements like:

Sensors have to be equipped with GPS modules

Efficient clustering algorithm is required.



F. Amin, A. H. Jahangir, and H. Rasifard, “Analysis of Public-Key Cryptography for

Wireless Sensor Networks Security”-(2008)

With the wide spread growth of applications of Wireless Sensor Networks (WSNs), the

need for reliable security mechanisms over networks has increased manifold[11]. They

provided security solutions in the domain of WSN. These solutions were usually based

on well-known cryptographic algorithms.

Drawbacks: Public key cryptography relies on computationally difficult mathematical

functions and cannot provide any indication of eaves dropping or guarantees key security.

S.Poornima, B.B.Amberker, “Tree-based Key Management Scheme for Heterogeneous

Sensor Networks”-(2008)

To achieve security in WSN, it is important to be able to encrypt the messages sent

between sensor nodes[12]. It is required to agree upon a common key before encrypting

the messages. The key management task is challenging due to resource constrained

nature of WSN. They were proposed a tree based key management scheme for

heterogeneous sensor networks. The scheme supports revocation of the compromised

nodes and the energy efficient re-keying.

Drawbacks: This scheme lacks in efficient storage for group keying in IEEE 802.15.4.

This method was difficult to set up securely. Cluster formation information is application

dependent.



T.Kavitha, D.Sridharan, “Security vulnerabilities in Wireless Sensor Networks: A

Survey”-(2009)

The significant advances of hardware manufacturing technology and the

development of efficient software algorithms make technically and economically

feasible a network composed of numerous, small, low-cost sensors using wireless

communications, that is, a wireless sensor network(WSN)[13]. Security is becoming

a concern for WSN protocol designers because of the wide security-critical

applications of WSNs. They proposed how WSN differs from wired network

and other wireless network and also basic information about the WSN and its security

issues compared with wired network and other wireless networks.



NETWORK SECURITY &CRYPTOGRAPHY

3.1 Network:

A network is a series of points or nodes interconnected by communication paths.

Networks can interconnect with other networks and contain sub-networks. A computer

connected to a non computing device (e.g., networked to a printer via an Ethernet link)

may also represent a computer network.

In order for a network to function, it must meet three basic requirements, it must provide

connections, communications and services.

‘Connections’ refers to the hardware.

‘Communications’ is the way in which the devices talk to each other.

‘Services’ are the things which are shared with the rest of the network

3.2 Sensor Network:

A sensor network comprises of sensor nodes and a base station. Each sensor node is

battery powered and equipped with integrated sensors, data processing capabilities and

short-range radio communications Due to their limited power and shorter communication

range, sensor nodes perform in-network data fusion.

Data fusion process:

A data fusion node collects the results from multiple nodes.

It fuses the results with its own based on a decision criterion.

Sends the fused data to another node/base station.



Advantages:

Reduces the traffic load.

Conserves energy of the sensors.

3.3 Cryptography:

All aspects such as security and integrity of information have been aided by rapid

advances in communication technology and networking. Hackers can utilize both active

and passive methods to overload networks and alter data. To provide Security and

integrity for information/data Cryptography came into existence.

Definition: Writing the messages in secret way is called cryptography [24].

3.3.1 Security:

Security is mainly of three types, namely;

1. Computer Security

2. Information Security

3. Network Security

3.3.2 Security Violations:

Copy a file without authentication during transmission.

Constructing own messages instead of intercepting.

Modifying messages by intercepting.

Delaying messages.

3.3.3 Security attacks:



1. Passive attacks

2. Active attacks

Passive attack attempt to learn or make use of information from the system but does

not affect system resources. An active attack attempts to alter system resources or affect

their operation.

3.3.4 Methods to achieve security goals:

Access control

Authentication

Encryption

Intrusion detection

3.3.5 Introduction to Cryptography:

In the era of information technology, the possibility that the information stored in a

person’s computer or the information that are being transferred through network of

computers or internet being read by other people is very high. This causes a major

concern for privacy, identity theft, electronic payments, corporate security, military

communications and many others. We need an efficient and simple way of securing the

electronic documents from being read or used by people other than who are authorized to

do it. Cryptography is a standard way of securing the electronic documents.

Basic idea of Cryptography:

Basic idea of cryptography is to mumble-jumble the original message into something that

is unreadable or to something that is readable but makes no sense of what the original

message is. To retrieve the original message again, we have to transform the mumble-

jumbled message back into the original message again.



3.3.6 Basic Terminologies used in Cryptography:

Cryptography is an important tool in securing information transactions for thousands of

years. It was originally intended to disguise messages so that adversaries could not

acquire or alter sensitive information. It is the science of mathematics to “Encrypt” and

“Decrypt” data. Cryptography enables us to store sensitive information or transmit it

across insecure networks like Internet so that no one else other than the intended recipient

can read it.

Data that can be read and understood without any special measures is called plain text or

clear text. This is the message or data that has to be secured. The method of disguising

plaintext in such a way as to hide its substance is called encryption. Encrypting plaintext

results in unreadable gibberish called cipher text. We use encryption to ensure that

information is hidden from anyone for whom it is not intended, even those who can see

the encrypted data. The process of reverting cipher text to its original plaintext is called

decryption. Cryptanalysis is the art of breaking Ciphers that is retrieving the original

message without knowing the proper key. Cryptography deals with all aspects of secure

messaging, authentication, digital signatures, electronic money, and other applications.

Cryptography has also been expanded to provide the following information security

requirements [24]:

1. Non-repudiation: Preventing an entity from denying previous commitments or

actions.

2. Integrity: Ensuring no unauthorized alteration of data.

3. Authentication: Verifying an entity’s identity

4. Confidentiality: Protecting the data from all but the intended receiver.

3.3.7 Cryptographic Algorithms:

Cryptographic algorithms are mathematical functions that are used in the encryption and

decryption process. A cryptographic algorithms works in combination with a key(a



number, word or phrase)to encrypt the plain text. Same plain text encrypts to different

cipher texts for different keys. Strength of a cryptosystems depends on the strength of the

algorithm and the secrecy of the key.

Cryptography is entrenched in higher mathematics: group theory, computational

complexity and even real analysis. Practical cryptography which is being used in the field

of information security uses either a key or a pair of keys for encryption and decryption,

depending on the algorithm. There are three types of algorithms available for practical

crypto-systems which can be used to accomplish the security.

1. Symmetric-key crypto-systems

2. Asymmetric-key crypto-systems

3. Public-key crypto-systems

Crypto-System Model:

The general basic model which is used for encryption and decryption is shown

below in figure 3.1. A message is to be transferred from sender to recipient across the

information channel and that message must not be accessible by intruders who are having

means of accessing the channel. The sender uses his key to scramble the message data

and generate cipher text. Although the algorithm which is used in the process of

scrambling or encrypting the message is known to public, the key which is used for

encryption is a secret component. Therefore, no one can divulge the message out of

cipher text without having the combination of particulars of encryption algorithm and the

key. The recipient uses the agreed algorithm and key to decrypt or descramble cipher text

which he received from the sender via an unsecured information channel.


Key One

Message

Intruder Key Two

Cipher Text Channel Cipher Text Message


Sender Recipient

Fig 3.1 Crypto System Model for encryption and decryption

Symmetric Key cryptosystem:

A symmetric key cryptosystem [24] can be used to implement a secure

communication system. The protocol for the secure communication with the symmetric

key cryptosystem can be explained as follows;

1. Sender and recipient agree on a cryptosystem.

2. Sender and recipient agree on a key.

3. Sender encrypts his plaintext message using the encryption algorithm and key. This

creates a cipher text message. Sender sends this cipher text to recipient.

4. Recipient decrypts cipher text message with the same algorithm and key and reads it

as plaintext.

Sender Recipient

Fig 3.2 Model for Encryption and decryption with Symmetric Key Algorithm

Suppose assume that,

M – Message

C (M) – Cipher text message

ESymKey - Encryption with the symmetric key


Sym Key

Message

Intruder Sym Key



DSymKey – Decryption with the symmetric key

The above figure illustrates the model of symmetric key crypto-system. According to

that;

At the senders end:

C (M) = ESymKey (M)

At the recipient’s end:

M = DSymKey [C (M)]

Examples of well-known symmetric algorithms include the Data Encryption

Algorithm (DEA) defined by the Data Encryption Standard (DES), and Triple-DES.

Asymmetric Key Cryptosystem:

The origin of public key cryptography is based on one-way function. One-way

functions [16] are relatively easy to compute, but significantly harder to reverse. That is,

given x it is easy to compute f(x), but given f(x) it is harder to compute x, i.e. it will take

more time to compute x from f(x). There are two more additional requirements for the

asymmetric key crypto-systems than symmetric crypto-system;

1. It is computationally hard to calculate private key from public key.

2. Cipher text which is generated by a public key can only be decrypted by the

corresponding private key.

The protocol for asymmetric key crypto-system can be outlined as follows;

1. Sender and recipient agree on a public key crypto-system.

2. Recipient sends his public key to sender.

3. Sender encrypts his message using recipient’s public key and send it out to the

recipient.



4. Recipient decrypts sender’s message using his private key.

Sender Recipient

Fig: 3.3 Model for Encryption and decryption with Asymmetric Key Algorithm

According to the above mentioned figure, an asymmetric crypto-system is following

encryption and decryption mechanism;

At the sender’s end:

C (M) = EPublicKey (M)

At the recipient’s end:

M = DPrivateKey [C (M)]

Public Key Crypto-System:

This project is based on the Public-Key cryptosystem.

The proposal of public key cryptosystems in 1976 by Whitfield Diffie and Martin

Hellman introduced a revolutionary way to address modern security issues such as key

management, authentication, non-repudiation, and signatures [14] in a digital

environment.

All cryptosystems are secure only if the difficulty of the mathematical problem

that they are based on should be determined to be hard. Public-key cryptosystems are


Public key

Message

Intruder Private Key



based on the intractability of one of three problems. These problems and the

cryptosystems based on them are:

1. The Integer Factorization Problem; RSA

2. The Discrete Logarithm Problem; DSA, Diffie-Hellman

3. The Elliptic Curve Discrete Logarithm Problem; ECDSA, ECDH

3.3.8 Overview of Public Key Cryptography:

Public Key cryptography uses two keys Private key (known only by the recipient) and a

Public key (known to everyone). The public key is used to encrypt the message and then

it is sent to the recipient who can decrypt the message using the private key. The message

encrypted with the public key cannot be decrypted with any other key except for its

corresponding private key.

Fig:3.4 Encryption process in the public-key cryptography

The following figure illustrates the decryption process in the public-key cryptography.


Message to be encrypted or plain text

Encryption Algorithm

Encrypted message or Cipher text

Public Key known to everyone

Message to be decrypted or cipher text

Decryption Algorithm

Decrypted message or Plain text

Private Key known only to receiver


Fig:3.5 Decryption process in the public-key cryptography

The public-key algorithm uses a one-way function to translate plain text to cipher text.

Then, without the private key, it is very difficult for anyone (including the sender) to

reverse the process (i.e., translate the cipher text back to plain text). A one-way function

is a function that is easy to apply, but extremely difficult to invert. The most common

one-way function used in public-key cryptography involves factoring very large numbers.

The idea is that it is relatively easy to multiply numbers even large ones, with a

computer; however, it is very difficult to factor large numbers. The only known

algorithms basically have to do a sort of exhaustive search (Does 2 go in to? Does 3? 4?

5? 6? and so on). With numbers 128 bits long, such a search requires performing as many

tests as there are particles in the universe.

3.3.8.1 RSA – Public Key Cryptography Algorithm:

Introduction to RSA Algorithm:

RSA is one of the most popular and successful public-key cryptography algorithms. The

algorithm has been implemented in many commercial applications. It is named after its

inventor’s Ronald L. Rivest, Adi Shamir, and Leonard Adleman. They invented this

algorithm in the year 1977. They utilized the fact that when prime numbers are chosen as

a modulus, operations behave “conveniently”. They found that if we use a prime for the

modulus, then raising a number to the power (prime - 1) is 1.

RSA algorithm and its security simply capitalize on the fact that there is no efficient way

to factor very large integers. If someone comes up with an easy way of factoring a large

number, then that’s the end of the RSA algorithm. Then any message encrypted with the

RSA algorithm is no more secure.



RSA Algorithm:

The encryption and decryption of this work is based on RSA algorithm. Before

encryption and decryption is done, we have to generate the key pair and then those keys

are used for encryption and decryption. The key generation, encryption and decryption

process of RSA are explained in the implementation part.

3.3.8.2 ECC Crypto system

Figure 3.6 sharing the sensitive data in network using ECC algorithm



In this architecture the user both sender and receiver generates the private and public

keys. While communicating both encrypts the data using others public key and decrypts

using their own private key.

SOFTWARE REQUIREMENTS & SPECIFICATIONS

4.1 Feasibility Study:

The feasibility study is an important factor in analyzing the capability of the project. The

key objective of the feasibility study is to weigh up three types of feasibility. They are:

a) Operational Feasibility

b) Technical Feasibility

c) Economic Feasibility

4.1.1 Operational Feasibility.

Operational feasibility is necessary as it ensures that the project developed is a successful

one. As the execution process of the proposed work is very much user friendly, the

operational feasibility of the project is high.

4.1.2. Technical Feasibility.

Technical feasibility analysis makes a comparison between the level of technology

available and that is needed for the development of the project. The level of technology

consists of the factors like software tools, machine environment, and platform developed



and so on. Since, the resources like Swing, QKDPs and security mechanism packages for

the development of the project are available, the project is technically feasible.

4.1.3. Economic Feasibility.

This is the most important part of the project because the terms and conditions for

implementing the project have to be economically feasible. The risk of finance does not

exist as the existing hardware is sufficient and the software is free of cost. Hence, the

system is economically feasible.

4.2 User Interface:

Describes the logical characteristics of each interface between the software product and

the users. This may include sample screen images, any GUI standards or product family

style guides that are to be followed, screen layout constraints, standard buttons and

functions (e.g., help) that will appear on every screen, keyboard shortcuts, error message

display standards and so on. It defines the software components for which a user interface

is needed. It also specifies the details of the user interface design that are to be

documented in a separate user interface specification.

4.2.1 GUI Components:

JButton, JLabel, JTextField, JTextArea, JFrame, JTabbedPane, JScrollPane, Container.

JButton:

JButton is used to send, clear, hopcount, process, store, back, generate to dataset,

receive, Add IDS Entry and More Systems.



JLabel

A display area for a short text string. A label does not react to input events. As a

result, it cannot get the keyboard focus. In the development environment, it will display

the To, From, Port, Intermediate System No., Intermediate System Names, Send data,

Received Data, source IP, Destination IP, Enter new rules in dataset.

JTextField

JTextField is a light weight component that allows the editing of a single line of

text. In the development environment, it gets the IP addresses, Port number, Intermediate

System No., Intermediate System Names from the user.

JTextArea

JTextArea is a multi-line area that displays plain text. In the development

environment, it is used to send the data and to receive the data. The user enters the

message to send the data.

JScrollPane

Provides a scrollable view of a light weight component. A JScrollPane manages a

viewport, optional vertical and horizontal scroll bars, and optional row and column

heading viewports.

JTabbedPane

A component that lets the user switch between a group of components by clicking

on a tab with a given title and/or icon. In the development environment, there are two

JTabbedPane are used. One is anomalous tab and normal tab.



Container

A generic Abstract Window Toolkit (AWT) container object is a component that

can contain other AWT components. Components added to a container are tracked in a

list. The order of the list will define the components front-to-back stacking order within

the container. If no index is specified when adding a component to a container, it will be

added to the end of the list (and hence to the bottom of the stacking order).

4.3 Hardware Interface:

Describes the logical and physical characteristics of each interface between the software

product and the hardware components of the system. This may include the supported

device types, the nature of the data and control interactions between the software and the

hardware, communication protocols to be used.

Hardware Requirements:

Processor : Pentium IV

RAM : 512 MB

Hard Disk : 20 GB

4.4 Software Interface:

Describes the connections between this product and other specific software components

(name and version), including databases, operating systems, tools, libraries, and



integrated commercial components. Identify the data items or messages coming into the

system and going out and describe the purpose of each. Describe the services needed and

the nature of communications. Refer to documents that describe detailed application

programming interface protocols. Identify data that will be shared across software

components. If the data sharing mechanism must be implemented in a specific way (for

example, use of a global data area in a multitasking operating system), specify this as an

implementation constraint.

Software Requirements:

Front End : Java, Swing

Operating System : WindowsXP

Data Base : MySQL

4.5 SQL Server 2005:

It included native support for managing XML data, in addition to relational data. For this

purpose, it defined an xml data type that could be used either as a data type in database

columns or as literals in queries. XML columns can be associated with XSD schemas;

XML data being stored is verified against the schema. XML is converted to an internal

binary data type before being stored in the database. Specialized indexing methods were

made available for XML data. XML data is queried using XQuery; Common Language

Runtime (CLR) integration is the main feature enabling one to write SQL code as

Managed Code by the CLR. SQL Server 2005 added some extensions to the T-SQL

language to allow embedding XQuery queries in T-SQL. It also defines a new extension

to XQuery, called XML DML that allows query-based modifications to XML data. SQL

Server 2005 also allows a database server to be exposed over web services using TDS

packets encapsulated within SOAP (protocol) requests.



SYSTEM DESIGN

Design and Testing are the actual process of producing a solution according to the

specification derived from the analysis stage.

5.1 System Preliminary Design:

Message browsing

Plaintext

Cipher text


SRC Node

DB

Encryption process

DESNode

Decryption process

Plaintext


Cipher text

Fig 5.1 Preliminary design of the proposed model

Functionality:

Initially a source(SRC) sensor node browses message (plaintext) from database

and encrypts that message using RSA keys. Then the encrypted message (Cipher text)

will be transferred to destination(DES) sensor node via the cluster header. Now DES

node decrypts the Cipher text into plaintext and reads the original message.

5.2 Data Flow Diagram:

A data-flow diagram (DFD) is a graphical representation of the "flow" of data through

an information system. DFDs can also be used for the visualization of data

processing (structured design). On a DFD, data items flow from an external data source

or an internal data store to an internal data store or an external data sink, via an internal

process DFD provides no information about the timing of processes, or about whether

processes will operate in sequence or in parallel.


http://en.wikipedia.org/wiki/Data_processing

http://en.wikipedia.org/wiki/Data_processing

http://en.wikipedia.org/wiki/Data_visualization

http://en.wikipedia.org/wiki/Information_system


Fig 5.2 Data flow diagram.

5.3 Use Case Diagram:

A use case diagram in the Unified Modeling Language (UML) is a type of behavioral

diagram defined by and created from a Use-case analysis. Its purpose is to present a

graphical overview of the functionality provided by a system in terms of actors, their

goals (represented as use cases), and any dependencies between those use cases.

The main purpose of a use case diagram is to show what system functions are performed

for which actor. Roles of the actors in the system can be depicted. Use Case diagrams are


Cluster Head

Node

Key Generation Using RSA

Node Details

Key Details

Communication Node1

Communication Node2

Sink


formally included in two modeling languages defined by the OMG: the Unified Modeling

Language (UML) and the Systems Modeling Language (SysML).

Fig: 5.3 Use case diagram.

5.4 Sequence Diagram:

A sequence diagram in Unified Modeling Language (UML) is a kind of interaction

diagram that shows how processes operate with one another and in what order and at a

specific time. It is a construct of a Message Sequence Chart. Sequence diagrams are

sometimes called event diagrams, event scenarios, and timing diagrams.


client1

Login

Cluster Head

Key_Reqest

Request Server

Response from Client


SinkCluster Head : (Cluster Head)

Node : (Node) Communication Node1...

Communication Node2

Rigitration

Accept

Path Request

Send Path

Key Request

Key Distribute

Forward Data

Forward

Forward

Fig 5.4 Sequence diagram.

5.5 Collaboration Diagram:

A collaboration diagram, also called a communication diagram or interaction diagram, is

an illustration of the relationships and interactions among software objects in the Unified

Modeling Language (UML). The concept is more than a decade old although it has been

refined as modeling paradigms have evolved. A collaboration diagram resembles a



flowchart that portrays the roles, functionality and behavior of individual objects as well

as the overall operation of the system in real time.

Cluster Head

Node

1: Rigitration

2: Accept

3: Path Request

4: Send Path

5: Key Request

6: Key Distribute

Sink

Communication Node1

Communication Node2

7: Forward Data

8: Forward

9: Forward

Fig: 5.5 Collaboration Diagram:

5.6 Component Diagram:

A component diagram in the Unified Modeling Language, depicts how sure wired

together to form larger components and or software systems. When using a component

diagram to show the internal structure of a component, the provided and required


http://en.wikipedia.org/wiki/Software_system

http://en.wikipedia.org/wiki/Unified_Modeling_Language


interfaces of the encompassing component can delegate to the corresponding interfaces of

the contained components.

Cluster Head

Node Registration

Key Generation

Key Distribution

Key Request

Node

Data Forwarding

Sink

Fig 5.6 Component Diagram

5.7 Activity Diagram:Describes the flow of control of the target system.



Fig: 5.7 Activity Diagram

5.8 State Machine Diagram:



A state machine diagram models the behavior of a single object, specifying the sequence

of events that an object goes through during its lifetime in response to events.

Authentication

Cluster Formation

Key Generation

Key Distribution

Key_Request

Data Forwarding

Fig: 5.8 State chart Diagram.

SYSTEM IMPLEMENTATION



Modular implementation:

The project mainly has been divided in to four modules. They are;

Cluster Formation

Routing in Sensor Networks(SNs)

Key Generation and distribution of keys

Encryption & Decryption

6.1 The Cluster Formation:

After sensor deployment, clusters are formed in an SN(Sensor Network) and

designed an efficient clustering scheme for SNs [9]. For the simplicity of discussion,

assume that each H-sensor can communicate directly with its neighbor H-sensors (if not,

then relay via L-sensors). All H-sensors form a backbone in an SN. After cluster

formation, a SN is divided into multiple clusters, where H-sensors serve as the cluster

heads. An illustration of the cluster formation is shown in Fig:6.1, where the small

squares are L-sensors, large rectangular nodes are H-sensors, and the large square at the

bottom-left corner is the sink. For the ease of execution, I considered all H-sensor, L-

sensors in a single host machine and confined all nodes to communicate in a single

cluster where each H-sensor can directly communicate with any of its L-sensors(if the

node is not a neighbor, then it can relay via other L-sensors).



Fig: 6.1.Cluster formation in a Sensor Networks (SN)

6.2 Routing in SNs:

In a SN, the sink, H-sensors and L-sensors form hierarchical network architecture.

Clusters are formed in the network and H-sensors serve as cluster heads. All H-sensors

form a communication backbone in the network. Powerful H-sensors have sufficient

energy supply, long transmission range, high date rate, and thus provide many advantages

for designing more efficient routing protocols [6]. Routing in a SN consists of two

phases: 1) Intra-cluster routing – each L-sensor sends data to its cluster head via multi-

hops of other L-sensors; and 2) Inter-cluster routing - a cluster head (an H-sensor)

aggregates data from multiple L-sensors and then sends the data to the sink via the H-

sensor backbone. The routing structure in an SN is illustrated in Fig:6.1. An intra-cluster

routing scheme determines how to route packets from an L-sensor to its cluster head. The

basic idea is to let all L-sensors (in a cluster) form a tree rooted at the cluster head H. (1)



If complete data fusion is conducted at intermediate nodes, (i.e., two k-bit packets come

in, and one k-bit packet goes out after data fusion) then a minimum spanning tree (MST)

consumes the least total energy in the cluster. (2) If there is no data fusion within the

cluster, then a shortest-path tree (SPT) can be constructed using either a centralized or

distributed algorithm. It consumes the least total energy.

6.3 Key Generation and Key Distribution:

This project makes use of RSA public-key Cryptosystem for key generation and

integrated QKDP’s for key distribution.

6.3.1 Key Generation:

The first step in RSA encryption is to generate a key pair. Two keys are generated of

which one is used as the public key and the other is used as the private key. The keys are

generated with the help of two large prime numbers. The keys are generated as follows:

1. Generate two large random primes p and q.

2. Compute n which is equal to product of those two prime numbers, n = pq

3. Compute φ(n) = (p-1)(q-1).

4. Choose an integer e, 1 < e < φ(n), such that gcd(e, φ(n)) = 1.

5. Compute the secret exponent d, 1 < d < φ(n), such that ed ≡ 1 (mod φ(n)).

6. The public key is (n, e) and the private key is (n, d). The values of p, q, and

φ(n) should also be kept secret.

n is known as the modulus.

e is known as the public exponent or encryption exponent.

d is known as the secret exponent or decryption exponent.



6.3.2 Key Distribution:

For key distribution process, QKDP’s were used with RSA in order to distribute the keys

to neighboring nodes by the cluster header(which acts as a Trusted Center).

Quantum Cryptography:

Quantum cryptography is only used to produce and distribute a key, not to

transmit any message data.

With the use of Quantum cryptography, the two communicating parties can be

able to detect the presence of any third party trying to gain knowledge of the key.

For secure communications, Quantum key distribution protocols(QKDP’s) are

used. It enables two parties (sensors) to produce a shared random bit string known

only to them, which can be used as key to encrypt and decrypt the messages.

Quantum cryptography easily resists replay and passive attacks.

An unique property of quantum cryptography is providing the ability to the both

communicating users to detect the presence of any third party trying to gain

knowledge of the key by using quantum super positions or quantum entanglement

and transmitting information in quantum states, by this eavesdroppers can be

detected.



Key Management Scheme:

This technique involves encoding information in quantum states(Qu-bits) as opposed to

classical communications use of bits. Usually, photons are used for these quantum states.

QKD divided into two main categories depending on which property they exploit.

Prepare and measure protocols (Calculate the amount of information that has been

intercepted).

Entanglement based protocols (Two quantum states of two(or more) separate

objects can become linked together in such a way that they must be described by a

combined quantum states, not as individual objects).

Performing a measurement on one object affects the other. If an entangled pair of objects

is shared between two parties(sensors), any one intercepting either object alters the

overall system revealing the presence of the third party and amount of information they

have gained.

6.3.3 Design Aspects:

TC(Trusted Center)-Cluster header and participant synchronize their polarization basis

according to pre-shared secret key. During session key distribution, the pre-shared secret

key together with random string are used to produce another encryption key to encipher

the session key. By this, a receiver will not receive the same polarization qu-bits even if

identical session key is retransmitted. Hence, the secrecy of pre-shared secret key can be

preserved and thus this secret key can be long term and repeatedly used between TC and

participant. Due to combined use of classical cryptographic techniques over quantum

channel, a receiver can authenticate user identity, verify the correctness and freshness of

the session key and detect the presence of eavesdroppers.



Level0:

Fig:6.2 Distribution of Session Key with Quantum Cryptography

Level 1:

Fig:6.3 Generation of Session key with Quantum Cryptography


Trusted center

Receiver

Secret Key

Secret Key

Session Key

Encrypted Msg by Session Key

Level1

Key Generation

Sender

Sec Key

Session key

Qubit Generation

Random String Generation

Session Key Generationononon


6.4 Encryption and Decryption:

6.4.1 Encryption:

Encryption is done using the public key component e and the modulus n. To whichever

the particular node want to send the message, it encrypt the message with its public key

(e,n). Encryption is done by taking an exponentiation of the message m with the public

key e and then taking a modulus of it. The following steps are done in encryption:

1. Obtain the recipient’s public key (n,e)

2. Represent the plain text message as a positive integer m < n

3. Compute the cipher text c = m^e mod n.

4. Send the cipher text c to the recipient.



Fig: 6.4 Data Encryption process

To encrypt a message M the sender:

obtains public key of recipient KU={e,N}

computes: C=M^e mod N, where 0≤M<N


Get the original data and public key for encryption

Perform Encryption

If Encrypte

d

Get Encrypted data

Stop

No

Yes

Start

Exit


6.4.2 Decryption:

Decryption is done using the Private key. The node which is receiving the encrypted

message uses its own private key to decrypt the message. Decryption is similar to the

encryption except that the keys used are different.

1. Recipient uses his private key (n,d) to compute m = c^d mod n.

2. Extract the plaintext from the integer representative m.

NOTE: The message M must be smaller than the modulus N (block if needed)

Fig: 6.5 Data Decryption process


Start

Get Ciphertext and private key

Decrypt the encrypted data

Retrieve original data

Stop


6.5 Importance of RSA:

RSA algorithm had been in use for the past 25 years and it’s been one of the most

successful cryptography algorithms that the security world ever had. This is still widely

used in many applications even after hundreds of public key cryptographic algorithms

emerged after the invention of RSA algorithm. This algorithm is still in use because of its

security and easy implementation. RSA strengths make it most suitable for resource-

constrained systems. RSA provides greater security for a given key size and can be

efficiently and compactly implemented. These attributes make it well suited for systems

with constraints on processor speed, security, power consumption, bandwidth, and

memory. The RSA algorithm has been implemented in many applications and it is

currently one of the most popularly used encryption algorithm. The security of the RSA

algorithm lies in the fact that there is no good way of factoring numbers. No one till now

knows a way to factorize a number into its prime factors. As long as no one finds a way

RSA will be safe and will be one of the best encryption algorithms in use. If someone

comes up with a way to factorize algorithms, then that’s the end of RSA. If we consider

RSA vis-à-vis ECC, ECC is very much faster than RSA, but actually ECC is significantly

faster than RSA only when used with pre-computed values. That is, if we can store ECC

key in a small space and if we want to get the performance advantage, we have to store

some tables of pre-computed values. These tables can be as many as 20,000 bytes. But if

we don’t have 20,000 bytes of storage space lying around (say your smart card), we may

not be able to use the pre-computed tables. Then the ECC is not that much faster than

RSA. With ECC you can sign fast or save storage space, but you can’t do both. Of

course, saving storage space and transmission size may be reason enough.

Currently in the industry, RSA is winning. The key size, transmission size and signature

performance issues concern makers of small devices. But they often find that RSA is fast

and small enough. Sure, it’s not the fastest signer or the smallest key, but it still works

just fine. And RSA has a well-developed certificate infrastructure.



RESULTS AND DISCUSSIONS

Fig: 7.1 Number of participating nodes in a cluster

Fig: 7.1 define the number of nodes that are going to participate in the communication

process by forming a cluster (Group of nodes over a network).

Consider for an instance, if a cluster is formed by 4 nodes viz..node1,node2,node3,node4

and so on, then among the existing nodes, any node can be a cluster header and via this

cluster header a MST(Minimum Spanning Tree) is constructed and the communication

will takes place via this particular node.



Fig: 7.2 Formation of Cluster

Fig: 7.2 depict the formation of cluster with the neighboring nodes in a network. Among

the existing nodes, any node can be a cluster header and the remaining nodes have to

register with the particular header in order to participate in the communication process.

The cluster header can be changed dynamically.



Fig: 7.3 Cluster Header Registration

Fig: 7.3 represent the registration of the cluster header. All the details of each and every

node are stored in a central data base. The cluster header gets the details of its

neighboring nodes from the data base.

Fig: 7.4 Registering Process of Cluster Header



Fig: 7.4 represent the registering process of cluster header. All other nodes (neighbor)

which want to participate in the communication process have to send a registration

request to cluster header.

Fig: 7.5 Confirmation of Cluster Header

Fig: 7.5 define the confirmation of the cluster header by generating a unique password.

This header in future communicates with its neighboring nodes with the help of this

password.



Fig: 7.6 Neighboring Nodes Registration Process with Cluster Header

Fig: 7.6 represent the neighboring nodes registration with the header (the nodes those

want to participate in the communication process).

Fig: 7.7 Registration Request

Fig: 7.7 indicate the request that has been made by a node to header in a network.



Fig: 7.8 Acceptance of Request by Header

Fig: 7.8 indicate the request that has been accepted by a header node and it sends a reply

message of its confirmation by generating a unique node ID in a network



Fig: 7.9 MST Request for Communication

Fig :7.9 indicates that the MST(Minimum Spanning Tree) request generated from cluster

header to the requested node, it(the requested node) can get the coordinates by providing

the information like node name, unique ID generated to it ,by then a MST can be

constructed by using the ID’s.

NOTE: The steps from Fig 7.6 to Fig 7.9 are common for all other nodes in a network if

they want to takes place in the process of communication.



Fig: 7.10 Key Request Form for a Node for Communication

Fig: 7.10 indicate that the key request generated from cluster header to the requested

node, it (the requested node) can get the key by providing the information like node

name, unique ID generated to it, by then a private key is generated to it by the cluster

header that which would be provided for the further communication with other nodes in

the network.



Fig: 7.11 Co-ordinates Identification of a Node

Fig: 7.11 tell us the identification of coordinates of a node in order to locate that

particular node in a network by the production of its unique ID.



Fig: 7.12 Locating Neighboring Nodes

Fig: 7.12 depict the location of neighboring nodes and then it constructs a MST via

cluster header node to the neighboring nodes.



Fig: 7.13 Key Requests for Communication

Fig: 7.13 indicates the key request made by a particular node to the cluster header by

producing its public key (Unique ID).



Fig: 7.14 Generation of Private Key

Fig: 7.14 represents the generation of private key. Here, the cluster header here acts as a

trusted centre (TC) and generates a private after verifying the details produced by a

particular node. Then by using the secret key, the requesting node can communicate with

the other neighboring nodes (of its requirement).



Fig: 7.15 Destinations and Message Content

Fig:7.15, here the node that want to communicate has provide the details like the data

that want to transfer and the destination node that it wants to communicate with.



Fig: 7.16 Encrypted Form of the Message Content

Fig: 7.16 represent the encrypted form of the message that is to be transferred by using

the Cryptographic algorithm.



Fig: 7.17 Receiving Message at Destination

Fig: 7.17 shows that the message encrypted there at the sender side and at the receiving

end are same. Hence the sensor nodes communicated successfully.



CONCLUSION AND FUTURE SCOPE

8.1 Conclusion:

In this project, a model was implemented which provides internal security in a network

and also an efficient key management scheme has been proposed for a sensor network.

This scheme utilizes the fact that a node communicates with only a small portion of its

neighbors and thus greatly reduces the communication and computation overheads of key

setup. A public-key algorithm RSA is used along with QKDP’s to further improve the

key management scheme for generation and distribution of secret keys. These keys were

used to encrypt, transmit and decrypt sensitive data being shared among nodes within a

network.

8.2 Future Scope of the work:

This work can be extended in real world heterogeneous sensor networks by making use

of Elliptic Curve Cryptography (ECC) algorithm to achieve stronger information

security. Authentication would be still provided in an easier manner by making use of

ECC algorithm on wireless sensor networks. By making use of ECC, further reduction in

storage space, computational overheads, power consumption could be achieved because

of its shorter key length.



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