Steganography via Sound Effects in PowerPoint Files

GRADUATE PROJECT TECHNICAL REPORT

Submitted to the Faculty of the Department of Computing Sciences Texas A&M University-Corpus Christi

Corpus Christi, TX

in Partial Fulfillment of the Requirements for the Degree of Master of Science in Computer Science

by Preethi Chittimalla

Summer I 2011

Committee Members Dr. Mario Garcia _____________________________ Committee Chairperson

Dr. Hongyu Guo _____________________________ Committee Member

Dr. John Fernandez _____________________________ Committee Member

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Abstract

Communication of data by maintaining confidentiality is a major issue everywhere, so to

increase the security a non – conventional approach called steganography is proposed.

“Steganography” is an art of “hiding data within data” [1,2]. In general, Stego means

“covering” and graphia means “writing”. Combining these two terms gives the meaning of

steganography, i.e. ”covered writing”[2]. It is similar to cryptography with a small

difference; cryptography makes use of scrambling of data techniques whereas

steganography makes use of the carrier file of some type to store the information [6]. It is

easy to capture a cryptographic message but it is not easy to know the steganographic

message. “Steganography’s objective is to transmit a message from one end to the other via

harmless carrier/medium. By making use of this method, the attacks on the message are very

rare because the attacks do not know what the actual message is [2]. Embedion with

steganography will produce much more secure data communication. It can be used for

different types of data formats, of which the most popular are .gif, .txt, .wav, .bmp and .jpeg.

These types of files are called carriers. In general, the most common examples of

steganography are invisible ink, covert channel and microdot [2,6]. This concept is used

everywhere or in any technology to send confidential information.

A new type of steganography approach has been proposed named PowerPoint file

Steganography”. Data hiding is done in the sound/custom animation effects of the

PowerPoint file. To implement this technique, a codebook is designed which contains the

confidential details of the sound effects and the text information that needs to be transferred.

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TABLE OF CONTENTS Abstract ...................................................................................................................................ii

Table of Contents....................................................................................................................iii

List of Figures ........................................................................................................................v

1. Background and Rationale………………………………………………………….….......1

1.1 Steganography………………………………………………………………………….1

2. Carrier Methods………….....................................................................................................2

2.1. Text File Steganography……………………………………………………………...2

2.2. Image Steganography……….......................................................................................4

2.2.1. Least Significant Bit Replacement Technique………………...........................5

2.2.2. Algorithm for LSB…......………………………………..………...…………..6

2.3. Audio Steganography...................................................................................................7

2.3.1. Algorithm for Wavelet Transform……………………………………................8

2.4. Video Steganography……………………………………………………...................9

2.4.1MPEG-4 Technique.…………………………………..……………..………......9

2.5. Animation File Steganography….....……………………..………….………….......11

2.5.1 Animation Code Book…………………………..……….……………........11

2.5.2. Embedding Process…………..…..……....………..………………..…......12

3. Research Objectives...........................................................................................................13

3.1. Data Storage in Sound Effects (PowerPoint Files Steganography)….………..….....13

4. Design…………..………..…………………………………….…………...…….……....14

4.1 Designing Codebook & Software…………….……………………………...………15

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5. Implementation…………..………..…………………………………….……...….....….19

6. Testing & Evaluation…..…..…………………………………….………….......…….….24

6.1 Testing Methodology………………………………………………………………..24

6.1.1 Mapping File…………………………………………………………….24

6.1.2 Testing at Sender Side……………………………………………….…..25

6.1.3 Testing at Receiver Side…………………………………………………27

6.2 Evaluation…………………………………………………………………….……..28

7.Results…………………………………………………………………………………….29

8. Conclusion…………..………..…………………………………….…………...…….….32

9.Future Scope………………………………………………………………………………33

10.References…………..………..…………………………………….…………...…….…34

List of Figures Figure 1.1 Idea of Steganography…………………………………………………..….....2

Figure 2.1 LSB for Image-Steganography………………………………………………..6

Figure 2.2 Wavelet Implementation…..………….……………………………………….8

Figure.2.3 Coding of Objects in MPEG-4…………….....................................…………10

Figure 5.1 Codebook text file…………………………………………….…………..….20

Figure 5.2 Plain PowerPoint file with no hidden data………………………………...…21

Figure 5.3 Entering the confidential data that needs to be embedded……....……….......22

Figure 5.4 Message acknowledgement saying the data is embedded…………………...22

Figure 5.5 Hiding data in PowerPoint file using sound effects……………………..…...23

Figure 5.6 Receiver end displaying the embedded text……………………..……….…..24

Figure 6.1 Animation Codebook………………………………………………………...25

Figure 6.2 Embedding data into PowerPoint File…………………………..…………...26

Figure 6.3 Message Acknowledgement……………………………………………..…..27

Figure 6.4 Retrieved Data……………………………………………………………….27

Figure 7.1 Embed or retrieve the data……….…………….……….……….……….…..30

Figure 7.2 Data Hiding in PowerPoint file…………………………………..……….….30

Figure 7.3 Retrieved Message is displayed…………………………………………...…31

Table 4.1 Sample Code Book…………………………………………………………....16

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1. Background and Rational

1.1 Steganography

Steganography is the art of “hiding data within data”, so this section discusses the details

of data hiding techniques in the carrier medium [1]. Generally, there are two types of

steganographic methods for hiding the data. The first method is Spatial Domain Embedding and

the second method is Frequency Domain Embedding [5]. Spatial Domain Embedding uses the

LSB (Least Significant Bit) method, i.e. least significant bits are used to hide the data. The LSB

selection is done randomly in a noisy area so as to reduce the suspect rate [5]. In Frequency

Domain Embedding, Discrete Cosine Transformation (DCT) and Discrete Wavelet

Transformation (DWT) are well known methods. In DCT, initially the image is split into low and

high frequency components that results in spectral sub-bands [10]. Based on these two methods,

different carrier mediums are used for steganography. The process of steganography is illustrated

in Figure 1.1.

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Alice Bob

Figure: 1.1 Idea of Steganography [1]

2. Carrier Methods

2.1 Text Files Steganography

Text file steganography is the most widely used steganography method. To hide a secret

message in a text file is a tedious task due to the very little data availability. So, it would be hard

to add redundant characters or bits to the content [1, 2]. There are several methods for

accomplishing text-based steganography. The two important methods for hiding information in

text are a) Editing the Text Format and b) Jumbling the Text. In the text formatting method, the

actual message is embedded into a randomly selected text that is later transmitted [6]. The best

example for editing the text format method is “Data Hiding within Data” method [6]. A stream

of text data is considered and some characters are selected in that data, for hiding confidential

information. This confidential information is replaced with the characters in that stream of text

and sent to the receiver so that confidentiality is not violated [1]. The following example

Secret Message

Embedding Medium

Message Embedding Function

Stego message

Message Retrieval Function

Secret Key

Secret Message

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illustrates this [1]:

“Some event can run each text in natural sequence in design effectiveness”

From this text first letter of each word is considered to retrieve the desired output. “Some

Event Can Run Each Text In Natural Sequence In Design Effectiveness”. From this the

hidden/confidential data is “secret inside”.

The text file steganography is arduous considering the amount of time and effort involved

in selecting text [2]. In the “Jumbling method”, all the words or textual data are scrambled so

that the message content is hard to crack. There are some more methods that are available to

implement the text file steganography; one among them is "Semantic Method”. In this method,

some of the words from the input stream of data are replaced with its synonym or by

abbreviating the words or by applying punctuation marks in proper places [13]. The major

advantage of this method is securing information by using Optical Character Recognition.

However, in semantic method very little data is hidden.

There are numerous methods that have been proposed for data storage in text files, some

of them are: Formatting Text Method, Line Shifting method, Word Shifting method and Feature

Specific Encoding method [5]. In Line Shifting method, there is vertical transformation of lines

to some degree (2-3 centimeters). This transformation is done based on the line’s position from

the stationary line, which creates distinct shapes of text. In the Word Shifting method,

“Horizontal Spaces method” and “Distance between Words” methods are used, which is used to

evaluate hidden data. Results from Word Shifting are more reliable than Line Shifting. In Feature

Specific Encoding method, the major goal is to format the text by changing the attributes (i.e.

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length of letters d, b etc...) [1, 13].

2.2 Image Files Steganography

Image files are also used to hide data for communication. An image file is an array of

numbers that constitutes light intensities [1, 3]. In this approach, the data can be hidden in a color

image or a gray scale image. Gray-scale images were given more importance because of their

variation in shades. This will increase the scope for hiding information [3, 5]. In the process of

embedding the image file, the confidential data that should be hidden in the image file is first

embedded using a cryptographic algorithm. Then the embedded data is embedded into the image

file, which in turn results in a stego-image [1, 2]. Then a stego-key is used during the hiding

process to send the image securely to the receiver. After the image is received at the other end,

the receiver will extract the data from the image. In order to extract the message, the receiver

requires a shared secret key. The extraction process detailed is a cryptographic algorithm or a

stego-key approach. To improve this process, message compression can be applied, so that data

security is maintained at a higher degree [2].

Compressing an image produces better results during steganography. There are two types

of image compression techniques: Lossy Compression and Lossless Compression. The Lossy

Compression method has various disadvantages and not an efficient technique. This project

focuses on the Lossless Compression method. It was found that the results produced by the Loss

Less Compression are much better. In the Lossless Compression technique, the originality of the

digital image is maintained. Some of the examples of Lossless Compression are Microsoft’s

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Bitmap, CompServ’s GIF etc. [2]. In Lossless Compression technique, 256 shades of grey for 8-

bitimage sizes are used [1, 2]. There are many other methods for hiding message bits. One of the

efficient methods of storing the message bits is “Least Significant Bit Replacement Technique”

which is one among many techniques used for data hiding.

2.2.1. Least Significant Bit Replacement Technique

All image steganography techniques try to alter insignificant information. Of them, LSB

encoding is the most simple and common approach for embedding data. By altering the least

significant bit, the image quality is not compromised. Hence, this will help in preserving the

confidential information [2, 5]. In this technique, the data that needs to be hidden is embedded in

the least significant bits (LSB) of the pixels of the cover image. This modified image is known as

“stego-image”. Due to the changes in the bytes of the image, there might be some traces of

isolated pixels if the pixel location was uniform. Hence, proper care should be taken while the

cover image is selected [5]. The most important factor that should be considered while selecting

a covered image is that the image should be a composition of large amounts of small details [2].

While storing the data using 24-bit image, 3 bits can be stored in each pixel. The green,

blue and red color components were represented in bytes [5]. For example, if a 24-bit color

image is considered and 3 pixels were selected as shown in Figure 2.1

(00101111 01010100 11011000)

(11001000 11111100 11011000)

(00110111 00010111 01011011)

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If a character “A” holding a binary value 10000001 is inserted, the following results are

produced.

(00101111 01010101 11011000)

(11001001 11111100 11011001)

(00110111 00010111 01011011)

So from the example, the letter “A” is embedded into the first 8 bytes, which in turn

modifies 3 bits.

Figure: 2.1 LSB for Image-Steganography [3]

2.2.2. Algorithm for LSB

The following are the sequence of steps that were followed to hide the data [5]:

Step 1: Actual image and the data to be hidden were read.

Step 2: n bits shift operation was performed

Step 3: Shift operation was performed for the cover image with 11110000 so that

MSB’s were set to 0

Step 4: After the shift operation both are bitored.

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This results in changes to the n LSB bits and hence the data or the confidential image is

stored into the cover image [5]. An additional functionality (hiding the bit in a pixel) to the

existing LSB method can be used to make the data more secure. In order to do this, the pixel is

made to satisfy some minimum conditions that are stated as follows, 1) Adjacent neighbor’s

brightness variance is made to be very high or very low or else the pixel will be skipped [3, 5].

Hence these tests were passed by the pixel. This process is done so that the analyst can know

about the pixels. 2) During this process if any of the pixels does not pass the tests the pixel

retains its original value. 3) Soon after the stego-image is received the original image should be

destroyed so that the attacker cannot track the hidden information [5].

2.3. Audio Steganography

Many techniques were proposed in order to perform steganography in audio files

amongst which, LSB (Least Significant Bit) method is the most widely used method [2, 3, 5].

Another method named “Lifting Wavelet Domain” is used for hiding in the audio files [1]. The

pseudo-noise is embedded so that the security factor can be improved. In this technique, the

wavelet is placed in the fifth resolution so that the output is a string, which consists of six sub-

bands (CA1, CD1, CD2, CD3, CD4, and CD5) as shown in Figure 2.2 [4]. Every sub-band

belongs to a specific resolution level. From the above sub-bands it is determined that, to

calculate the fifth level transform; the first level transform should be calculated first so that CA1

and CD1 coefficients are determined [4]. For the next phase, the transformation for CA1

coefficients is performed. Hence this procedure is followed to generate all the coefficients. After

the coefficients are generated, a check is performed to find if there are any strings that are left

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over in the lower level and then those are also transformed until the string results in fifth

resolution level [4].

Temporal signal

CA1 CD1

CA2 CD2

CA3 CD3

CA4 CD4

CA5 CD5

Figure.2.2 Wavelet Implementation [4] 2.3.1. Algorithm

Here are the steps that are implemented for hiding data [5]:

1) Fifth level transforms are applied on discrete samples and are filtered to produce integer

coefficients. Threshold value is computed with the integer coefficients.

2) Now the steam of string is jumbled by random number generator and hidden with secret key.

3) The String is replaces based on the obtained threshold value.

Finally an inverse LWT is performed. Then the coefficients are converted into time

domain to produce a time stego signal [8].

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2.4. Video Steganography

Even though image based steganography is widely used, it still has certain limitations. In

an image only little information is stored, but a video that is composed of images and audio,

stores huge volumes of data [1, 2]. As most of the video steganographic techniques are lossy,

they are not useful for document hiding. So, a new digital video steganographic technique

(MPEG-4) is proposed that consists of new video structures [7]. This technique increased the

security of the document files without any loss of information.

In this approach, the multimedia data is coded based on objects. Combination of the

elements such as text, audio, video, images or individual is considered as an object [10]. Hence

these objects are known as audio-visual objects.

2.4.1. MPEG-4 Technique

This technique makes use of parallel data structures and MPEGLets, which provide

security and huge storage capacity respectively. It is less complex when compared to other

techniques of digital video steganography [7]. In this technique, a scene is created based on

objects that are present in the specification list of each component and based on the temporal

relations it possesses. Based on these objects, the scene events are described [7]. In this

approach, the text is coded, which is hidden in a MPEG-4 video. MPEG-4 elementary streams

are produced using Java jargon. After this process, MP4Box software is used to synchronize the

MPEG-4 objects and to multiplex them into single video bit stream [7]. As shown in the Figure

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2.3

Figure 2.3 Coding of Objects in MPEG-4 [4]

The following is the mechanism, which is under progress during data hiding in MP4Stego

technique [7].

1) |S| = |C| + 1/3 |D| [7]

Where S= Stego object size

C= Cover object size

D= Document size

The main aim of MPEG-4 technique is to increase the information secrecy, provide

authentication and integrity while the documents are accessed [7, 10]. Hence this reduced the

chance of detecting the messages hidden by the MP4Stego.

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2.5. Animation Files Steganography

Another novel approach of hiding data using PowerPoint files gained importance

recently. In this approach, the data is stored in various animation-timing effects. This approach

uses, animations for applying on text, graphs, and images. Even by the addition of animation

effects the content of the file is not changed [8, 9]. The timing effects and sound effects used for

the animations are used to control the flow of data.

The animation effects can be grouped as: Entrance, Emphasis, Exit and Motion Paths.

Objects are entered with animations in the presentation by making use of entrance effect [8].

Making use of emphasis effect does animation of objects. To make the objects leave the slide,

show an exit effect is being used. Motion paths are used to allow the objects to move around the

slide show [8]. The animation effect is made interactive by having its own timing parameter [9].

2.5.1. Animation Codebook

A codebook is created which consists of all the information related to the effects that are

present in that technique. The codebook will be very helpful to store information in these timing

effects [8, 9]. Next section will state the basic principles required for preparing a codebook.

1) All the three types of animations effects: Entrance, Emphasis/Motion paths and exit should

be re-grouped.

2) At least one-animation effects must be applied for every character of the hidden message [8].

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2.5.2. Embedding Process

This process makes use of two general assumptions and three embedding rules [8].

Asumption1: Both transmitter and the receiver maintains the same animation codebook.

Assumption2: The Embedding animation effect that was applied for the object should

follow the human perception.

Rule 1: Entrance animation is applied if the embedded message object was not on the

slide.

Rule 2: If the entrance effect is used for embedding the object then one can make use of

Emphasis/motion paths or exit animation category.

Rule3: If the embedded object has the emphasis/motion paths animation category, the

only option for that embedded object was exit animation category.

Hence by making use of the animation codebook, assumptions and the rules data is

hidden into the PowerPoint file.

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3 Research Objectives

Based on the present analysis about different carrier media, it was found that the video

file steganography is the most reliable, efficient and expensive method for storing large volumes

of data. But even other methods of steganography are of greater importance based on the usage.

By analyzing different carrier media it is found that PowerPoint file steganography is a new

carrier medium for storing confidential information. Hence, by performing deep analysis on the

PowerPoint files, it is found that there is a possibility of a new approach for storing information

in PowerPoint slides. Section 3.1 illustrates this approach.

3.1. Data Storage in Sound/ Custom Animation Effects

A new technique for storing data in animation files has been proposed recently. In this

technique, the confidential message is embedded or stored in the sound effects of the PowerPoint

files. This can be achieved by collecting all types of sound/custom animation effects that are

present in the PowerPoint files. Based on the type of the sound it is assigned with a character or

number to each sound effect. In this way, a codebook/text file is generated for sound/custom

animation effects and is shared with the sender and the receiver. At the sender side, the message

is hidden into the PowerPoint files by making use of codebook and finally sent to the receiver.

The receiver then retrieves the information from the presentation slides by mapping the sound

effects with the codebook.

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4. Design

As discussed in section 2.5, a codebook implementation that is shared between the sender

and the receiver helps to hide confidential information. Some of the assumptions and rules that

are followed for designing the codebook are [8]:

All the sound effects that are available in the Microsoft PowerPoint are taken into

consideration. If there are not enough sound effects available in the software that are installed in

the local machine, they can be downloaded from the Microsoft official website.

At first a randomly available PowerPoint file is given as input for embedding the data.

Initially, it checks for the number of slides that are available and if the numbers of slides are less

than the actual message length then the program adds additional slides to the file.

Asumption1: Sender and Receiver maintains the same codebook to embed or retrieve the

information.

Assumption2: Using the Microsoft PowerPoint 2010 software the current project was

developed.

Assumption3: To make the project more efficient custom animation effects were also

included

Rule 1: Based on the message size the number of slides should be automatically added.

Rule 2: If one of the sound effects was assigned to any variable it cannot be used again

by any other variable or number.

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4.1 Designing Codebook & Software

A codebook application is designed using .NET technology. All the characters in

alphabet (a-z) and numeric data (0-9) are given as input for this application. Along with these

inputs all the predefined sound/custom animation effects are also submitted as input to the

application. Then a random generator function is called by the application, which assigns a

random sound/animation effect to the individual variable or value. Then this randomly generated

codebook is written to a text file. This would be a major source for data hiding and it needs to be

maintained confidential.

This codebook is shared between the sender and the receiver to exchange the data

confidentially. The sender also sends a PowerPoint file along with the randomly generated

codebook. The PowerPoint file consists of additional information that is not related to the sender

and the receiver. This is to ensure data confidentiality in case of a man in the middle attack. The

PowerPoint file sent by the sender might have irrelevant text but sound/custom animation effects

that are used for that file are important for retrieving the data. There might be a problem that

could be faced when an attack occurs i.e. contamination of data. To safeguard the file from

contamination, any cryptographic technique can be used for additional confidentiality. This

would be the overall idea of transmitting the confidential data. But, to embed the data by

selecting individual sound effect with reference code and to retrieve the data could be a very

tedious task. A tool has been designed for both the sender and the receiver to embed or retrieve

the data.

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This tool is implemented using .NET technology. The sender gives all the input and also

the PowerPoint file to the application. Then the output is the PowerPoint file containing the

embedded data in it. The data that needs to be entered into the file is entered at run time. The

embedded file is then sent to the receiver. The receiver uses application at receiver's end to

retrieve the data. The input for the receiver’s application is the PowerPoint file with the

embedded data and the mapping file containing the codebook. When the receiver clicks on

retrieve button, the secret code will be displayed. Hence by making use of these two tools

(Embedding tool and the Retrieval tool), a secure transfer is performed. In the Table 4.1 is a

sample codebook that was resulted as output.

Table 4.1 Sample Code Book

Sound/Custom Animation Effect Alphabet/ Number

Arrow 1

Applause L

Bomb B

Breeze 2

Camera O

Cash register A

Chime Q

Click U

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Coin 3

Drum roll C

Explosion P

Hammer F

Push T

Suction V

Typewriter 9

Voltage Z

Whose K

Wind D

$CoverRightDown W

$checkboardacross 0

$circleout I

$combveritcal M

$coverright S

$coverdown 8

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$wiperight Y

$wipedown E

$wipeleft J

$wipeup 6

$pushright 5

$pushup R

$pushdown G

$pushleft X

$randombarshorizantal H

$random N

$randombarsvertical 4

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5. Implementation

The major goal of Steganography is to transmit data over a confidential media. Based on

the type of the application and the amount of data that needs to be transmitted carrier media will

be selected. PowerPoint file steganography is a good technique for storing small volumes of data.

In any steganographic technique there are two different phases. One is at the sender phase and

the other is the receiver phase. In the sender side, an embedding algorithm is designed to embed

the data into the PowerPoint file and at the receiver side retrieval algorithm is designed to

retrieve the information. These two (Embedding and Retrieval) algorithms are implemented in a

single application.

When the sender wants to embed the data, the application is deployed and the inputs are

submitted. All the resulted outputs are sent to the receiver. At the receiver end, the application is

deployed and all the outputs that are sent by sender are given as input. When the application is

set to run the secret message will be displayed. The sender side tool and the receiver side tool are

implemented in C#.NET. To deploy this application “Microsoft PowerPoint” driver should be

added to the references. This driver will be helpful to embed the custom animation/ sound effects

into the PowerPoint file randomly.

Creating codebook is another phase in this application. To create this codebook a good

random function is designed. To this random function, both the characters and the sound/Custom

animation effects are given as input and the output is a text file containing the mappings between

the characters and the sound/custom animation effects. To reduce the complexity this part of the

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program is also implemented in the same application (i.e. the embed/retrieval application). When

the application is deployed, the mapping file is generated at first and then the initial screen will

be displayed. The generated mapping file is saved on the desktop. So, whenever the application

is deployed different mapping file will be generated and saved on desktop of the local machine.

Similarly, the PowerPoint file that is given as input is stored in the local machine and taken as

input by the program/application.

In Figure 5.1 it is observed that a codebook generated randomly can contain the

alphabets, numeric data and the names of the sound/ custom effects.

Figure 5.1 Codebook text file

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Sender generates the codebook randomly and passes it as input to the application. A

PowerPoint file with irrelevant data is chosen and passed as input to the application. In Figure

5.2 one can see the PowerPoint file that is given as input.

Figure 5.2 Plain PowerPoint File with No Hidden Data

Then this PowerPoint file is given as input to the application that was developed to

embed the data and then the text or the confidential data is entered in the text field. Figure 5.3

shows that the confidential data is entered into the text field.

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Figure 5.3 Entering the confidential data that needs to be embedded

When the “embed message” button is clicked the data will be successfully embedded into

the PowerPoint file. Figure 5.4 shows the message of acknowledgement.

Figure 5.4 Message acknowledgements saying the data is embedded

During the embedding process the mapping file or the codebook will be scanned. Based

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on the secret message that is entered into the text field, the program will select the exact match of

the letter and related sound/custom animation effect. Then these selected effects are embedded

into the PowerPoint file randomly. i.e. if the related character is assigned with a sound effect

then that sound effect will be assigned to the slide. Figure 5.5 represents the assigned sound

effect to the first slide.

Figure 5.5 Hiding data in PowerPoint file using sound effects

In this way all the characters are embedded into the file by mapping with the

text/codebook that was generated. Finally the PowerPoint file and the codebook text file are sent

to the receiver separately. Receiver makes use of the retrieval part of the application and

retrieves the message. At first these two files are given as input to the program and then clicked

on retrieve then the message is viewed in an alert box as shown in the Figure 5.6.

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Figure 5.6 Receiver end displaying the embedded text

6. Testing & Evaluation

6.1 Testing Methodology

There are three phases of testing in this project they are: testing the mapping file

generation, testing the client side application and receiver side application.

6.1.1 Mapping file

To generate the mapping file a good random function should be used. To have efficient

results the file generated by this application should be unique every time it is generated. There

are many random functions available such as srand, drand etc. By making use of these existing

functions a new random function is created. It is designed in such a way that it will compare with

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already created logs and if there is an occurrence already then it again creates a new file. It is

found that, unique files are generated for every run or program execution. To make this

codebook more efficient, custom animation effects are also included. Figure 6.1 shows the

unique mapping file that is generated by the random function.

Figure 6.1 Animation Codebook

6.1.2 Testing at Sender side

At the sender side to perform embedding, care should be taken to while creating the

mapping file and the PowerPoint file that is given as input. PowerPoint file plays a major role i.e.

the data that is present in the PowerPoint file should be random or irrelevant to the secret

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message. If the information present in the file is related to the secret message it will become easy

for the intruder to crack the information or contaminate the information. So, proper care should

be taken while storing information into the file. Many tests were performed and handled; the

major problem would be when the number of slides is less than the secret message. In this case

extra slides will be added by the program and add some random text to the file. This random text

will be selected from the previous slides of the PowerPoint. It was found that there is no scope

for the intruder to crack the information because; every time a different mapping file is

generated. Figure 6.2 represents the data that is being embedded into the PowerPoint file.

Figure 6.2 Embedding data into PowerPoint File

Another important test case that should be handled is the data limitation. This application

will produce good results when very little data is stored i.e. about 2KB data. If the data exceeds

2KB there may be a chance to attack the data. Figure 6.3 represents the message storage

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acknowledgement.

Figure 6.3 Message Acknowledgement

6.1.3 Testing at Receiver side

In the receiver side proper care should be taken while submitting the inputs to the

application. One should make sure that the data is not contaminated in the middle by cross

checking the PowerPoint slides with the original slides. If it is found that the data is same then

the secret message should be retrieved. If there is some contamination in the data another request

should be made to the send. Figure 6.4 represents the retrieved information.

Figure 6.4 Retrieved Data

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6.2 Evaluation

PowerPoint file steganography in sound effects can be considered as a good technique for

storing the information. But, to improve the data storage capacity (i.e. to embedded more data)

custom animation effects are also used. By making use of both custom animation effects and the

sound effects, the data storage can be extended up to 10kb data. Always the sound effects are

given priority over the custom animation effects during the transition process. Selection of a big

PowerPoint file will solve the problems related to the size of data that needs to be embedded i.e.

if the PowerPoint file size is big large volumes of data can be stored. By making use of this

technique for storing data, it is analyzed that the results produced were promising. This technique

can be best applied during military application. As they require only single word to command the

army. If the size of the data is increased, it was found that there could be a possibility of

contamination of the data. To protect the data any cryptographic technique can be implemented.

By making use of the application that was developed for the sender side, many

codebooks were generated. All the test cases were handled for the sender side and receiver side

application. It was able to accept text related to alphabets and numbers of any range. There is no

limitation to data storage in reality but it would be restricted based on the size of the PowerPoint

files.

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7. Results

The results produced by this tool are very promising. There is no scope for cracking the

data if the codebook is maintained confidentially. There could be a possibility of “Man in the

Middle” attack to contaminate the data. So, to overcome that problem any kind of cryptographic

technique can be used.

When a person would like to transfer very little information confidentially then this

technique could be a better solution. This project is limited only to the alphabets and numeric

data but it can be extended to all types of characters available by including the outside

environment sound/custom effects into the PowerPoint file or downloading these effects from

Microsoft online. In Figure 7.2 it is shown that the data is stored into a PowerPoint file at the

sender side and in Figure 7.3 shows that the information is retrieved at the receiver side. A good

random function is designed in such a way that a unique codebook is generated every time. Both

the sender and the receiver can use the developed application and they can select an option i.e.

whether they want to embed the data or retrieve the data as shown in the Figure 7.1

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Figure 7.1 Embed or Retrieve the data

Figure 7.2 Data Hiding in PowerPoint file

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Figure 7.3 Retrieved Message is displayed

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8. Conclusion

Steganographic techniques are best suited as good carrier techniques for confidential data

transfers. There are different types of steganographic techniques for storing the data based on the

size. But to store little data there are not very good techniques available. So, to maintain

confidentiality and perform a secure communication “PowerPoint” files steganographic

technique can be considered as a better idea. So, the project work proposed a new technique of

storing the data i.e. in the sound/animation effects of a PowerPoint file. It is highly unimaginable

about data existence in sound/custom effects and it could be very hard to crack such data without

having the codebook or the details of the text. A user interface for both the sender and receiver is

designed to make their job easy so that even the novice user can use this application to exchange

the confidential information.

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9. Future Scope

This project is still in the initial stages of development and there is no proof of

concept for the project. Development should be improved to increase the storage capacity.

The major drawback with this application is the storage capacity of the secure data. To

overcome this drawback, audio file steganography and video file steganography can be

implemented on animation file steganography i.e. information is stored in the images,

videos and audio that are present in the PowerPoint file. So, by embedding data into the

images and audio of the PowerPoint file more information or data storage capacity can be

increased up to 1MB.

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10. References [1] Bret Dunbar. “Steganographic Techniques and their usage in an Open-System

Environment,”ACMSANS InstituteInfo.Secur., 2002. [2] J.RKrenn.“Steganography and Steganalysis,” IEEE Info.Assu.Secu., Jan 2004. [3] MathkourHassan, Sadoon A1 Batool and TouirAmeur, “A New Image

Steganography Technique”IEEE WirelessCom.,Ntwrk. And Mob. Cmptn., Oct 2008.

[4] Pooyan M and Delforouzi A. “LSB-based Audio Steganography Method Based onLifting Wavelet Transform,” IEEE International Symposium Sgnl. Proc and Info.Tech.., Dec 2007. [5] Neeta D, Snehal K and Jacobs D. “Implementation of LSB Steganography and

its Evaluation for Various Bits,” IEEE Digi. Info. Mang. pp 173-178, Dec 2006. [6] Shirali-Shahreza M and Shirali-Shahreza S. “Steganography in TeX Documents,” IEEE Intel’s. Sys. Knwldg. Engg. Vol 1, 2008 [7] De Carvalho DF, Chies R and Freire AP. “Video Steganography for ConfidentialDocuments: Integrity, Privacy and Version Control,” ACM 26th International,2008.

[8] Wen-Chao Yang and Ling-Hwei Chen. “A Novel Steganography Method via Various Animation Effects in PowerPoint Files,” ACM LibraryProceeding to Seventh International Conference on Machine Learning Cybernetics, July 2008.

[9] Min-QunJing,Wen-Chao Yang and Ling-Hwei Chen. “A New Steganography Method via Various Animation Timing Effects in PowerPoint Files,”ACM Library Proceeding to Eighth International Conference on Machine Learning Cybernetics,July2009. [10] Andreas Westfeld and Gritta Wolf. “Steganography in a Video Conferencing System,”Institute for Theoretical Computer Science,pp 32-47,Jan 1998. [11] MehdiKharrazi, Husrev T, Sencar, and NasirMemon. “Image Steganography: Concepts and Practice,” Stevens Institute of Technology pp 204-211, Feb 2004. [12] J Dong, W Wang and T Tan. “Multi-class Blind Steganalysis Based on

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Image Run-Length Analysis,” IEEE Assu.Secu.2009 [13] Lingyun Xiang, Xingming Sun, Gang Luo and Can Gan. “Research on Steganalysis for Text Steganography Based on Font Format,” IEEE Info.Assu. and Sec., Third International Symposium, Aug 2007.