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CRYPTOGRAPHY

1.INTRODUCTION

Cryptography helps ensure data privacy, maintain data integrity, authenticate communicatingparties, and prevent repudiation (when a party refutes having sent a message).

Basic encryption allows to store information or to communicate with other parties while

preventing non-involved parties from understanding the stored information or understanding the

communication. Encryption transforms understandable text (plaintext) into an unintelligible

piece of data (cipher text). Decryption restores the understandable text from the unintelligible

data. Both functions involve a mathematical formula (the algorithm) and secret data (the key).

Cryptographic Operations

Different cryptographic operations may use one or more algorithms. You choose the

cryptographic operation and algorithm(s) depending on your purpose. For example, for the

purpose of ensuring data integrity, you might want to use a MAC (message authentication code)

operation with the AES algorithm.

Data privacy

Cryptographic operations for the purpose of data privacy (confidentiality) prevent an

unauthorized person from reading a message. The following operations are included in data

privacy:

Encrypt and Decrypt

The encrypt operation changes plaintext data into cipher text through the use of a cipher

algorithm and key. To restore the plaintext data, the decrypt operation must employ the same

algorithm and key. Encryption and decryption may be employed at any level of the operating

system. There are three levels:

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1. Field level encryption

With field level encryption, the user application explicitly requests cryptographic

services. The user application completely controls key generation, selection, distribution,and what data to encrypt.

2. Session level encryption

With encryption at the session layer, the system requests cryptographic services

instead of an application. The application may or may not be aware that encryption is

happening.

3. Link level encryption

Link level encryption is performed at the lowest level of the protocol stack,usually by specialized hardware.

Data integrity, authenticity, and non-repudiation

Encrypted data does not mean the data cannot be manipulated (e.g. repeated, deleted, or even

altered). To rely on data, you need to know that it comes from an authorized source and is

unchanged.

Visual Cryptography

Visual cryptography, introduced by Naor and Shamir in 1995, is a new cryptographic

scheme where the cipher text is decoded by the human visual system. Hence, there is no need to

any complex cryptographic computation for decryption. The idea is to hide a secret message

(text, handwriting, picture, etc) in different images called shares or cover images. When the

shares (transparencies) are stacked together in order to align the sub pixels, the secret message

can be recovered. The simplest case is the 2 out of 2 scheme where the

secret message is hidden in 2 shares, both needed for a successful decryption. This can be further

extended to the k out of n scheme where a secret message is encrypted into n shares but only k

shares are needed for decryption where k

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Few years later, Verheul and Tilborg developed a scheme that can be applied on colored

images. The inconvenient with these new schemes is that they use meaningless shares to hide the

secret and the quality of the recovered plaintext is bad.

More advanced schemes based on visual cryptography were introduced where a colored

image is hidden into multiple meaningful cover images. Changetal.introduced in 2000 a new

colored secret sharing and hiding scheme based on Visual Cryptography schemes (VCS) where

the traditional stacking operation of subpixels and rows interrelations is modified. This new

technique does not require transparencies stacking and hence, it is more convenient to use in real

applications. However, it requires the use and storage of a Color Index Table (CIT), in order to

losselessly recover the secret image. CIT requires space for storage and time to lookup the table.

Also, if number of colors c increases in the secret image, CIT becomes bigger and the pixel

expansion factor becomes significant which results in severe loss of resolution in the camouflage

images.

Chang and Yu introduced a advanced scheme for hiding a colored image into multiple

images that does not require a CIT. This technique achieves a lossless recovery of the secret

image. This paper introduces an improved scheme based on Changs technique in order to

achieve the secret image lossless and with slight increase in the computational complexity of the

algorithm.

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2. ANALYSIS

The analysis is the process of understanding the system at a greater depth,

identifying the missing functions with an intention to improve it through better methods and

procedures. The Requirement analysis is done in order to understand the problem, the

Software system is to solve. Requirements analysis is on identifying what is needed from the

system, not how the system will achieve its goals. The goal of

requirements specification phase is to produce the software requirements specification

document. The person responsible for the requirements analysis is often called the

analyst.

In this phase we study the system and observe the problem of existing

system and think how to cover the problems (problem analysis). There are three major

activities in this phase are Problem analysis, Feasibility study and Software requirement

specifications. The requirement document must specify all the functional and Performance

requirements, the formats of inputs and outputs and all design constraints that exist due to

political, economic, environment and security reasons.

The phase ends with validation of the requrements specified in the

document. Validation is often done through requirement review , in which a group of

people including representatives of the client critically reviews the requirement

specifications.

2.1 PROBLEM ANALYSIS

System analysis is the process of gathering and interpreting facts,

diagnosing problems and using the information to recommend improvements to the system.

Only after the systems analysis we can begin to determine how and where a computer

information system can benefit all the users of the system. This accumulation of the system

is called a system study. In this phase we analyze the problem to get a clear understanding of

the problem. We study the existing system and observe the problems present in it, and then

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try to recover from them. The system that we are developing should overcome all the

problems.

This current system is any application that uses the modern encryption

technique. There are many traditional encryption techniques for securing the data. Theproblem with the earlier traditional technique is that we have lot of computation to be done.

To keep out data secure we use large numbers and more number of computations to confuse

the eavesdropper or the cryptanalyst. Though we are providing security with this kind of

approach we are burdening our self with lots of calculations.

2.2 FEASIBILITY STUDY

The feasibility study is to determine whether the system requestedis feasible or not. This is to identify the objectives of a new system. Before solving a problem

one must know what the problem is. This phase starts as soon as a user or a member of a

particular department recognizes a problem and initiates a request to computerize the

existing manual system or to modify the current computerized system.

The study is carried out by a small group of people who are familiar

with systems analysis and design process. Fact-finding techniques are used to gather the

required information.

The major purposes of this study are given below:

Identify the responsible user and to develop an initial scope of the system. This may

involve conducting a series of interviews to see which users are involved in and

which users are affected by the proposed project.

Identify the current deficiencies in the users environment. This involves preparing a

list of functions that are missing or operating unacceptably in the existing system.

Determine objectives for the new system. This involves preparing a list of existing

functions, which are to be reimplemented and new functions that are to be added.

Determine whether it is feasible to automate the system. This will involves some

approximate estimates of the schedule and cost to build a new system.

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Three key considerations are involved in the feasibility analysis:

1.Economic Feasibility

Economic analysis is the most frequently used method for

evaluating the effectiveness of a candidate system. More commonly known as cost/benefit

analysis, the procedure is to determine the benefits and savings that are expected from a

candidate system and compare them with costs. If benefits out weigh costs, then the decision

is made to design and implement the system. Otherwise, further justification or alterations in

the proposed system will have to be made if it is to have a chance of being approved. This is

an ongoing effort that improves in accuracy at each phase of the system life cycle.

The current project is economically feasible because the organization, which is sponsoring to

develop this system, has enough funds and they are ready to release the funds required by the

development team and also the developers could be economically justified for their work.

2. Technical Feasibility

Technical feasibility centers on the existing computer system (hardware,

software, etc.) and to what extent it can support the proposed addition. This involves

financial considerations to accommodate technical enhancements. If the budget is a serious

constraint, then the project is judged not feasible. The present project is

considered to the technically feasible as the technical requirements, which could be satisfied

very easily. We have the enough technological aspects to implement the above problem.

Hence the project is technically feasible.

3.Operational Feasibility

Proposed projects are beneficial only if they can be tuned into

information systems that will meet the organizations operating requirements. Simply stated,

this test of feasibility asks if the system will work when it is developed and installed. Are

there major barriers to implementation?

Here are questions that will help test the operational feasibility of a project:

Is there sufficient support for the project from management? From users? If the

current system is well liked and used to the extent that persons will not be able to see

reasons for change, there may be resistance.

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Are the current business methods acceptable to the users? If they are not, users may

welcome a change that will bring about a more operational and useful systems.

Have the users been involved in the planning and development of the project? Early

involvement reduces the chances of resistance to the system and in general andincreases the likelihood of successful projects.

Will the proposed system cause harm? Will it produce poorer results in any respect

or area? Will loss of control results in any area? Will accessibility of information be

lost? Will individual performance be poorer after implementation than before? Will

customers be affected in an undesirable way? Will the system slow performance in

any area?

Issues that appear to be relatively minor in the beginning have ways of growing

into major problems after implementation. Therefore, all operational aspects must be

considered carefully.We can say after studying the proposed system that the project looks

operationally feasible, as there is good support from management and the users involvement

in planning and development is appreciable.

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There is a communication gap between these people. A basic purpose of

SRS is to bridge this communication gap. SRS is the medium through which the client and

user needs are accurately specified; indeed SRS forms the basis of software development.An

important purpose of the process of developing an SRS is helping the clients to understand

their own needs.

1.A good SRS provides many benefits. Some of the goals it accomplishes are:

2.Establishing the basis for agreement between the client and supplier on what the software

product will be reducing the development cost.

3.The preparation of the SRS forces rigorous specification of the requirements before the

design begins. Careful development of an SRS can reveal omissions, inconsistencies and

misunderstanding early in the development cycle, which can considerably reduce cost.

4.Providing a reference for validation of the final product .The SRS assists in determining if

the software meets the requirements.

Hardware Requirements:

To run our system the minimum hardware we need is

Processor : Pentium III

RAM : 128 MB / 256 MB (Recommended)

Hard disk : 20 GB

Monitor : 15 / User choice

Resolution : 800*600 pixels

Key board : Standard QWERTY 104 keys / or any

CD Drive : 52x CDROM

Floppy Drive : 1.44

Printer : Laser jet

Mouse : Any standard Mouse

Software Requirements:

The software requirements required to run this application are:

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Operating System : Win 9x/ XP

Programming Tool : Java 1.4.2

4.DESIGN

Design is the first step in the development phase for any techniques and principles for the

purpose of defining a device, a process or system in sufficient detail to permit its physical

realization.

Once the software requirements have been realized, analyzed and specified the software

design involves three technical activities design, coding, generation and testing that are required

to build and verify the software.

The design activities are of main importance in this phase, because in this activity,

decisions ultimately affecting the success of software implementation and its ease of

maintenance are made. These decisions have the final bearing upon reliability and

maintainability of the system.

4.1 System Design

UML Description

The Unified Modeling Language (UML) is a standard language for specifying,

visualizing, constructing, and documenting the artifacts of software systems, as well as for

business modeling and other non-software systems. The UML represents a collection of best

engineering practices that have proven successful in the modeling of large and complex

systems. The UML is a very important part of developing object oriented software and the

software development process. The UML uses mostly graphical notations to express the design

of software projects. Using the UML helps project teams communicate, explore potential

designs, and validate the architectural design of the software.

Building Blocks of the UML:

The vocabulary of the UML encompasses three kinds of building blocks:

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1. Things

2. Relationships

3. Diagrams

There are three classifications of UML diagrams:

Behavior diagrams. A type of diagram that depicts behavioral features of a system or

business process. This includes activity, state machine, and use case diagrams as well as

the four interaction diagrams.

Interaction diagrams. A subset of behavior diagrams which emphasize object

interactions. This includes communication, interaction overview, sequence, and timing

diagrams.

Structure diagrams. A type of diagram that depicts the elements of a specification that

are irrespective of time. This includes class, composite structure, component,

deployment, object, and package diagrams.

System Architecture:

Finding sub systems during system design has many similarities to finding

objects during analysis. System decomposition is constantly revised whenever new issues

are addressed. The initial sub system decomposition should be delivered from the

functional requirements.A starting point is to take the use cases and assign the

participating objects that have been identified in each of them to the sub systems.

As the complexity of systems increases, the specification of the system

decomposition is critical. Moreover, subsystem decomposition is constantly revised

whenever new issues are addressed. Subsystems are merged into alone subsystem, a

complex subsystem is split into parts, and some subsystems are added to take care of new

functionality. The first iterations over the subsystem decomposition can introduce drastic

changes in the system design model. These are often best handled through brainstorming

sessions.Here, the sender is the active participant through out the process. The receiver is

the passive participant as he comes in to the picture only if the sender sends an secret

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image. The sender encrypt the secret image in the cover images and send it to the

receiver. Every time, the secret image is encrypted in the cover images.

Subsystem Services:

A subsystem is characterized by the services it provides to other subsystem. A service is

a set of related operations that share a common purpose.

The set of operations of a sub system that are available to other subsystems form the

subsystem interface. Subsystem Interface includes the name of the operations, their

parameters, their types and their return values.

The following are the subsystem services provided in our application:

1.Image passing to Receiver: This sub-system does the job of passing cover images to

the receiver. As it has to offer security, it does not output the secret image that it takes from

sender to receiver. It computes the final values and finally shows the end result of the

computation. This subsystem service forms the backbone of the project.

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: Sender :Receiver Initiate Key

Generation,Enc

rypt

Decrypt

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2.Embedding the secret image in to the cover images:This sub-system takes care of

splitting the secret image in to two parts and embedding the two parts of the secret image

into the cover images

Boundary Conditions:

During this activity we review the design decisions we made so far and identify

additional conditions i.e., how the system is started, initialized, shutdown and how to deal with

major failures such as image corruption.

Configure: For each persistent object, we examine in which use cases it is created or

destroyed. We determine whether the encrypting is being done in the standard format of any

other method.

Start up and Shutdown: For each component we add three use cases to start, shutdown and

configure the component.

Exception Handling: For each type of component failure we decide how the system should

react. In general exception is an event or error that occurs during the execution of the system.

Exceptions are caused by different sources.

Hardware Failure: Hardware ages and fails. For example, failure of the network link, can

damage the security of the images being transferred.

Uml diagrams

CLASS DIAGRAM

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class Class Model

.

rsion EA 7.0 Unregistered Trial Version








master

+ decrypt() : void

+ encrypt() : void

+ receive() : void

+ send() : void

encrpty

- key: int

- port_no: int

+ browse_image() : void

+ priview() : void

decrypt

- key: int

- port_no: int

+ decrypt() : void

+ view() : void

USECASE DIAGRAM

uc Class Model

0 Unregistered Trial Version EA 7.0 Unregistered Trial Version EA 7.0 Unregi















sender

browses the image

to encrypt

provides the key and port

number to encrypt

sends the encrypted

message

receiver

provides the port

number and key

decrypts the data

received

views the received

image

master

SEQUENCE DIAGRAM

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sd Class Modelnreg s ere r a ers on . nreg s ere r a ers on .

nregistered Trial Version EA 7.0 Unregistered Tr ial Version EA 7.0 U








master

sender receiver

encrypts the image()

provides the key and port number()

sends the encrypted image to the receiver()

views the incrypted image()

receives the encrypted image()

decrypts the encrypted image by giving the key()

ACTIVITY DIAGRAM

act Class Model EA 7.0 Unregistered Trial Version EA 7.0 Unregi

EA 7.0 Unregistered Trial Version EA 7.0 Unregi














start

sender browses for theimage that is to be

encrypted and sent

sender provides the key

and port number to

encrypt the image

after the image is

encrypted the sendersends the image

master

receiver provides the key and

port number to decrypt

decrypts the image

views the decrypted

image

stop

4.2 Object Design

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4.2.1 Object Specification

The system design model focuses on the subsystem decomposition

and global system decision such as hardware/software mapping, persistent

storage or access control. We identify to level subsystems and define them

in terms of the services they provide.

Specification activities during object design includes

a. Identifying missing attributes and operations

b. Specifying type, signature and visibility.

c. Specifying constraints.

d. Specifying Exceptions

Attributes and Operations:

a. Attributes: In this, we can identify attributes of the operation.

b. Operation: Operation is a property of the objects.

c. Attributes:

Attributes represent the properties of individual objects; only the

attributes relevant to the system should be considered.

5.2.1.1 Type, Signature and Visibility

The type of an attribute specifies the range of values the attribute

can take and the operations that can be applied to the attribute.

Given an operation, the tuple mode out of the types of its parameters

and the type of the return value is called the signature of the operation.The Visibility of an attribute or an operation specifies whether other

classes can use it or not.

UML defines three levels of visibility:

Private : A private attribute can be accessed only by the

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class, which it is defined.

Protected : A protected attribute or operation can be accessed

by the class in which it is defied and on any

descendant of the class

Public : A public attribute or oration can be accessed

by

any class.

Visibility : Here variables are private and functions are public.

4.3 Constraints

Constraints:

We attach constraints to classes and operations to more precisely

specify their behavior and boundary cases. The following are the

constraints in the application:

1) The user should enter the image for encryption in a Unicode format.

2) Fields must not contain null values.

3) The message should be padded to multiples of 2048 bits or 1024 bits.

Invariants:

These represent conditions on the attributes of a class that are

always true.

The invariants in our application are:

1. The image should not be blank

2. Both the cover images should be of the same side.

3. The secret image should be one-third the size of cover images.

Preconditions:

A precondition is a predicate that must be true before an operation is

invoked. Preconditions are associated with a specific operation.

Preconditions are used to specify constraints that a caller must meet before

calling an operation.

1. Both the users should all be online during the generation of keys.

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2.The sender must have the knowledge of the receivers IPaddress

Post conditions:

A post condition is a predicate that must be true after an operation is

invoked. Post conditions are associated with a specific operation. Post

conditions are used to specify constraints that the object must ensure after

the invocation of predation.

1. The secret image is to be saved by the corresponding receiver.

2. The receiver and Sender should be acknowledged after the process

is completed.

4.4 Exceptions

Exceptional conditions are usually associated with the violation ofpreconditions. Exceptions can be found systematically by examining eachparameter of the operation and by examining the status in which theoperation may be invoked. Here, we specify constraints that the caller needsto satisfy before invoking an operation.

a. When specified ip address of a sender node is not available on the

network, then necessary action is to be performed.

b. If image passing between receivers fails due to some socket

exceptions, they need to be handled.

c. If network connections fail in the middle of the sending process, thenthe sending process needs to be re-started.

d. When handling strings and converting them to BigInteger, we need to

take care of the necessary type casting between objects.

Associations

send

Many senders send the images at the same time.

Encrypt

*

Sender Encrypt the Images

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Sender Receiver

Sender images1 *

**

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Can Serve

Sender can serve the images of receiver at the same time.

5.AlgorithmsThis proposed algorithm is a improvement of Changs et al algorithm, a new secret color

image sharing scheme based on visual cryptography which was proposed in 2002. The proposed

approach uses meaningful shares (cover images) to hide the colored secret image, which is split

in to two parts one with even number of locations and the other with odd number of locations

and treated with both the cover images to reduce the threat of vulnerability. The recovery

process is loss less. The scheme defines a new stacking operation (XOR) and requires a

sequence of random bits to be generated for each pixel.

Method description

Assume that a gray image (H) with 256 colors which is the secret image to be hidden.

Each color can be represented as an 8-bit binary vector. This image is split into 2 sub images,

where the first sub image consists of all the pixel values with even number locations of the

image H and the other sub image with odd number of locations of H. The main idea is to hide the

two sub images into the two original (cover) images and thus we obtain 4 camouflage images.

Here we expand each pixel into m sub pixels and embed them into n shares. This scheme uses

m=9 as an expansion factor. The resulting structure of a pixel can be represented by an nx9

Boolean matrix S=[Sij] where (1i n, 1j9) and Sij =1, if and only if, the jth subpixel in the

ith share has a non-white color. To recover the color of the original secret pixel, an XOR

operation on the stacked rows of the n shares is performed

Hiding Algorithm

For a 2 out of 2 scheme, the construction can be described by a collection of 2x9 Boolean

matrices C. If a pixel with colork=(k1k2k8)2 needs to be shared, a dealer randomly picks an

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integer r between 1 and 9 inclusively as well as one matrix in C. The construction is considered

valid if the following conditions are satisfied:

Ki=S1jS2j

Where Ki=S1jS2j and j= i if ir

Note that the number of 1s in the first row of S must exceed the number of 0s by one.

Steps of the Algorithm

Take a colored secret image Hmn of size mxn and choose any two arbitrary cover images

C1mnand C2mn of size mxn.

Split Hmn into two subimages He and Ho where He consists of all pixel values in the even

positions of the secret image and Ho consists of all pixel values in the odd positions of the

secret image.

Scan through He and Ho and convert each pixel Heij and H

oij to an 8-bits binary string

denoted as k= (k1k2k8) 2

Select a random integerrp, where 1

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Fig 1:Secret Sharing algorithm flowchart

Fig 2:Secret Sharing recovering algorithm flowchart

6.System Testing and Implementation

Testing is the major quality control measure employed for software development.

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Its basic function is to detect errors in the software. During requirement analysis and

design, the output is document that is usually textual and non-textual. After the coding phase,

computer programs are available that can be executed for testing purpose. This implies that

testing has to uncover errors introduced during coding phases. Thus, the goal of testing is to

cover requirement, design, or coding errors in the program. The starting point of testing is unit

testing. In this a module is tested separately and often performed by the programmer himself

simultaneously while coding the module.

The purpose is to exercise the different parts of the module code to detect coding errors.

After this the modules are gradually integrated into subsystems, which are then integrated

themselves too eventually forming the entire system. During integration of module integration

testing is performed. The goal of this is to detect designing errors, while focusing the

interconnection between modules. After the system was put together, system testing is

performed. Here the system is tested against the system requirements to see if all requirements

were met and the system performs as specified by the requirements. Finally accepting testing is

performed to

demonstrate to the client for the operation of the system.

For the testing to be successful, proper selection of the test case is essential. There are

two different approaches for selecting test case. The software or the module to be tested is

treated as a black box, and the test cases are decided based on the specifications of the system ormodule. For this reason, this form of testing is also called black box testing.

The focus here is on testing the external behavior of the system. In structural testing the

test cases are decided based on the logic of the module to be tested. A common approach here is

to achieve some type of coverage of the statements in the code. The two forms of testing are

complementary: one tests the external behavior, the other tests the internal structure. Often

structural testing is used for lower levels of testing, while functional testing is used for higher

levels.

Testing is an extremely critical and time-consuming activity. It requires proper planning

of the overall testing process. Frequently the testing process starts with the test plan. This plan

identifies all testing related activities that must be performed and specifies the schedule,

allocates the resources, and specifies guidelines for testing. The test plan specifies conditions

that should be tested; different units to be tested, and the manner in which the module will be

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integrated together. Then for different test unit, a test case specification document is produced,

which lists all the different test cases, together with the expected outputs, that will be used for

testing. During the testing of the unit the specified test cases are executed and the actual results

are compared with the expected outputs. The final output of the testing phase is the testing report

and the error report, or a set of such reports. Each test report contains a set of test cases and the

result of executing the code with the test cases. The error report describes the errors encountered

and the action taken to remove the error.

Error MessagesThe term error is used in two different ways. Errors refer to the discrepancy between

computed and observed values. That is error refers to the difference between the actual output of

the software and the correct output. In this interpretation, error essentially is a measure of the

difference between the actual and the ideal. Error is also used to refer to human action thatresults in the software containing a defect or a fault. This detection is quite general and

encompasses all phases. The consequence of thinking is the belief that the errors largely occur

during

programming, as it is the can see, the errors occur through the development. As we can see, the

errors occur throughout the development process. However, the cost of

connecting the errors of different phases is not the same and depends upon when the error was

detected and corrected. The cost of correcting errors in the function of where they are detected.

As one would expect the greater the delay in detecting an error after it occurs, the more

expensive it is to correct it. Suppose an error occurs during the requirement phase and it was

corrected after the coding then the cost is higher than correcting it in the requirements phase

itself. The reason for this is fairly obvious. If there was error in the requirements phase that error

will affect the design and coding also. To correct the error after coding is done require both the

design and the code to be changed there by increasing the cost of correction.

The main moral of this section is that we should attempt to detect the errors that occur in

a phase during the phase itself should not wait until testing to detect errors. This is not often

practiced. In reality, sometimes testing is the sole point where errors are detected. Besides the

cost factor, reliance on testing as a primary source for error detection and correction should be a

continuous process that is done throughout the software development. In terms of the

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development phase, what this means is that we should try to validate each phase before starting

the next.

Testing Techniques

Testing is a process, which reveals errors in the program. It is the major quality measure

employed during software development. During testing, the program is executed with a set of

conditions known as test cases and the output is evaluated to determine whether the program is

performing as expected. In order to make sure that the system does not have errors, the different

levels of testing strategies that are applied at differing phases of software development are:

Unit Testing

Unit Testing is done on individual modules as they are completed and become executable. It is

confined only to the designer's requirements.

EACH MODULE CAN BE TESTED USING THE FOLLOWING TWO

STRATEGIES:

Black Box Testing

In this strategy some test cases are generated as input conditions that fully execute all

functional requirements for the program. This testing has been uses to find errors in the

following categories:

Incorrect or missing functions

Interface errors

Errors in data structure or external database access

Performance errors

Initialization and termination errors.

In this testing only the output is checked for correctness. The logical flow of the data is not

checked.

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White Box Testing

In this the test cases are generated on the logic of each module by drawing flow graphs of

that module and logical decisions are tested on all the cases. It has been uses to generate the test

cases in the following cases:

Guarantee that all independent paths have been executed.

Execute all logical decisions on their true and false sides.

Execute all loops at their boundaries and within their operational

Execute internal data structures to ensure their validity.

Integration Testing

Integration testing ensures that software and subsystems work together as a whole. It

tests the interface of all the modules to make sure that the modules behave properly when

integrated together.

System Testing

Involves in-house testing of the entire system before delivery to the user. Its aim is to

satisfy the user the system meets all requirements of the client's specifications.

Acceptance Testing

It is a pre-delivery testing in which entire system is tested at client's site on real world

data to find errors.

Validation Testing

The system has been tested and implemented successfully and thus ensured that all the

requirements as listed in the software requirements specification are completely fulfilled. In

case of erroneous input corresponding error messages are displayed.

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COMPILING TEST

It was a good idea to do our stress testing early on, because it gave us time to fix some of

the unexpected deadlocks and stability problems that only occurred when components were

exposed to very high transaction volumes.

EXECUTION TEST

This program was successfully loaded and executed. Because of good programming there

was no execution error.

OUTPUT TESTThe successful output screens are placed in the output screens section.

Testing is the process of finding differences between the expected behavior specified by

system models and the observed behavior of the system.

Testing process:

The testing process that is followed for each object of the system is discussed

below in detailed object wise.

1 Object Name: Sending Image

2 Test Criteria: Encrypting the original image

3 Testing Approach: Black Box Testing

TEST CASE EXECUTION AND ANALYSIS:

Test case 1:

Test case ID Test case Description Expected Result Actual Result

Go2Frame1 Browse the Hidden Image, Next screen should Next screen is

Cover Image1 and Cover be displayed displayed

Image2 and click on next

Go2Frame2 Browse the Hidden Image, Next screen should Exception arises

Cover Image1 and Cover be displayed Size of first image

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Image2 and click on next should be one-third of

Second image.

Test case 2:

Test case ID Test case Description Input data Expected Result Actual Result

Dest-Frame1 Enter the Key Numeric Accepts the values Accepted

Alphabets Accepts the values Accepted

Alphanumeric Accepts the values Accepted

Dest-Frame2 Enter the port Numeric Accepts the values Accepted

Number Alphabets Invalid data Rejected

Alphanumeric Invalid data Rejected

Test case 3:


Dest2-Frame1 Enter the port Numeric Accepts the values Accepted

Number Alphabets Invalid data Rejected


Dest2-Frame2 Enter the port Numeric Invalid data Rejected

Address Alphabets Accepts the values Accepted


Test case 4:


Rec2 Decryption Numeric Invalid data RejectedAddress Alphabets Accepts the values Accepted


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7.CONCLUSION

This project is on a topic that has been an active research area in the field of Network

Security and Visual Cryptography. We have taken utmost care to assure that the project meets

the requirements of the algorithm. The main aim of the project was to impart high security to

images. We chose to implement the sending of secret image securely with the help of two

algorithms called the Hiding algorithm for embedding the secret image successfully in the cover

images and Recovery algorithm for decrypting the secret image successfully from cover images.

We have developed this system keeping in view all the factors in view and provided a

walkthrough model interface. The beauty of the approach employed during the design and

coding phase is that it is very simple to understand, very transparent to the users, very robust in

protecting the security and highly reliable in terms of execution. Extra efforts have been put in to

ensure the security of the data. The security of the data has been given the topmost priority

through out the program and hence we feel that we have been successful in our aim.

8.SCOPE

Can be implemented in all kinds of organizations whether small or large

Needs no extra costs for implementation

Complex cryptographic algorithms are not needed

The threshold technique, plus resizing, returns the decoded image to its original form

i.e. removes the graying effect.

As future work, this scheme can possibly be modified reduce the noise obtained during

transformation. The recovery process of both secret images should remain loss less while

using the same expansion factor as described in this project.

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9.BIBLOGRAPHY

1. A. Shamir, How to share a secret, Commun. of the ACM, Vol. 22 (1979) pp. 612613.

2. E.R.Verheul and H.C.A.van Tilborg.Constructions and properties ofkout ofn visual secret

sharing schemes. Design Codes and Cryptography, 11(2):179196, 1997.

3. G. Ateniese, C. Blundo, A. De Santis, and D. R. Stinson, Constructions and bounds for visual

cryptography, Proc. 23rd International Colloquium on Automata, Languages, and Programming

(ICALP 96), (1996) pp. 416428.

4. T. Katoh and H. Imai, Some visual secret sharing schemes and their share size, Proceedings

of International Conferences on Cryptology and Information Security, (1996) PP. 4147

5. M. Naor and A. Shamir, Visual cryptography. Advances in Cryptology EUROCRYPT 94.

Lecture Notes in Computer Science, (950):112, 1995

6. C. Chang, C. Tsai, and T. Chen, A new scheme for sharing secret color images in computer

network. In the Proceedings of International Conference on Parallel and Distributed Systems,

pages 2127, July 2000.

7. Chang, C. C. and Yu. T. X., Sharing a Secret Gray Image in Multiple Images, in the

Proceedings of International Symposium on Cyber Worlds: Theories and Practice, Tokyo, Japan,

Nov. 2002, pp.230-237.

8. AN IMPROVED VISUAL CRYPTOGRAPHY SCHEME FOR SECRET HIDING

R.Youmaran, A. Adler, A. Miri School of Information Technology and Engineering (SITE),

University of Ottawa, Ontario, Canada

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