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An Approach to Enhance Image Encryption Using Block Based

Oct 23, 2014

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AN APPROACH TO ENHANCE IMAGE ENCRYPTION USING BLOCKBASED TRANSFORMATION ALGORITHM

by

MOHAMMAD ALI MOH'D BANI YOUNES

Thesis submitted in fulfillment of the requirements for the degree of Doctor of Philosophy

UNIVERSITI SAINS MALAYSIA 2009

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ACKNOWLEDGMENTS

"All praises and thanks to ALLAH"

I would like to express my sincere appreciation and heartfelt thanks to my supervisor, Dr. Aman Jantan, for his creative guidance, intellectual support, stimulating discussions and inspiring words. I am grateful for his excellent hospitality and wonderful attitude.

Also, I would like to thank Dr. Omar Abu Shqeer, Dr. Ahmed Abdel Raouf Younis, Dr. Samer Al-Dhalli, Dr. Ahmed Manasrah, and Dr. Ahmad Alzoubi for their constructive contribution, invaluable advice, critical comments and patience.

A great thanks from my heart to my parents for their prayers, my wife for her patience and support, my sons and daughter for their patience too, and my father in law, mother in law, brothers, sisters, friends, and colleagues for their encouragements.

Finally, I would like to thank all lecturers, administration, and staff of Universiti Sains Malaysia and all academic and non academic staff of the School of Computer Science for Graduate Studies for their help and support.

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TABLE OF CONTENTS Page TITLE ACKNOWLEDGEMENTS TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF ALGORITHMS LIST OF APPENDICES ABSTRAK ABSTRACT CHAPTER ONE: INTRODUCTION 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Introduction Research Motivations Symmetric Key Algorithms Image Encryption Using Block-Based Transformation Algorithm Hiding Technique Goal, Scope, and Objectives of the Research Thesis Structure i ii iii vii ix xi xii xiii xv 1 1 3 5 6 8 8 9 12 12 13 15 21 27 30 31 33 36 38

CHAPTER TWO: LITERATURE REVIEW 2.1 2.2 Introduction Digital Images 2.2.1 Digital Image Formats 2.3 Cryptographic Systems 2.3.1 Block and Stream Ciphers 2.4 Encryption Algorithms 2.4.1 Data Encryption Standard (DES) Algorithm 2.4.2 Blowfish Algorithm 2.4.3 Advanced Encryption Standard (AES) Algorithm 2.4.4 Serpent Algorithm

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2.4.5 Twofish Algorithm 2.4.6 RC6 Algorithm 2.4.7 MARS Algorithm 2.4.8 Triple-DES Algorithm 2.4.9 IDEA Algorithm 2.5 Current Research in Image Encryption 2.5.1 A new Image Encryption Approach Using Combinational Permutation Techniques 2.5.2 A General Cryptanalysis of Permutation-Only Multimedia Encryption Algorithms 2.5.3 Techniques for a Selective Encryption of Uncompressed and Compressed Images 2.5.4 Chaos-Based Image Encryption Algorithm 2.5.5 Analysis and Comparison of Image Encryption Algorithms 2.5.6 Image Encryption Using Fractional Fourier Transform and 3d Jigsaw Transform 2.5.7 Image Encryption for Secure Internet Multimedia Applications 2.5.8 Image and Video Encryption Using Scan Patterns 2.5.9 A New Chaotic Image Encryption Algorithm 2.5.10 Image Encryption and Decryption with Residual Intelligibility Measurements 2.5.11 Lossless Image Compression and Encryption Using SCAN 2.6 Steganography Technique for Digital Images 2.6.1 Cryptography and Steganography of Video Information in Modern Communication 2.6.2 A Technique for Image Encryption Using Digital Signature 2.7 Image Security Measurements 2.7.1 Image Correlation 2.7.2 Image Histogram 2.7.3 Image Entropy 2.7.4 Image Similarity 2.8 Summary

39 39 40 42 42 43 44 45 46 47 48 48 49 50 52 52 53 55 57 57 58 59 60 62 64 65

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CHAPTER THREE: A MODEL TO ENHANCE IMAGE ENCRYPTION USING BLOCK-BASED TRANSFORMATION TECHNIQUE 3.1 3.2 Introduction Model Description 3.2.1 Transformation Technique 3.2.2 Encryption Process 3.2.3 Key 3.3 Security Measures 3.3.1 Image Correlation 3.3.2 Image histogram 3.3.3 Image Entropy 3.3.4 Image Similarity 3.4 The Technique of Hiding Information in the Image Data 3.4.1 Data Mixing (Sender Side) 3.4.2 Data Extracting (Receiver Side) 3.5 3.6 Decryption Process Summary

67 67 67 71 77 78 78 79 88 90 92 94 94 96 99 100

CHAPTER FOUR: IMPLEMENTATION, TESTING AND RESULTS ANALYSIS 4.1 4.2 4.3 4.4 Introduction Implementation Architecture Experimental Design Testing and Results 4.4.1 Correlation Test 4.4.2 Entropy Test 4.4.3 Histogram Test 4.4.4 Similarity Test 4.4.5 Hiding Efficiency 4.4.6 Retrieving the Original Image 4.5 Discussion 4.5.1 Shortcomings of the Proposed Technique 4.6 Summary

101 101 102 103 104 106 116 119 123 125 129 130 133 134

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CHAPTER FIVE: DISCUSSION AND FUTURE WORK 5.1 5.2 Introduction Technical Contribution 5.2.1 Strength and Efficiency of the Technique 5.3 Economical Contribution of the Research 5.3.1 Knowledge Gain 5.3.2 Security Enhancement 5.4 Future Work 5.4.1 Random Factor CHAPTER SIX: CONCLUSION REFERENCES APPENDICES LIST OF PUBLICATIONS

136 136 136 137 141 142 143 144 145 148 150 160 184

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LIST OF TABLES

2.1 2.2 2.3 2.4 2.5 3.1 3.2 3.3 3.4 3.5 3.6 3.7 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9

Image color space versus bit depth (bpp) BMP file header Comparison of the algorithms used for image encryption Value of r (or rs) interpretation An example to illustrates the histogram data points Transformation table example The color value of pixel representation The horizontal correlation between adjacent elements of the image The vertical correlation between adjacent elements of the image The diagonal correlation between adjacent elements of the image The opposite diagonal correlation between adjacent elements of the image The probability of gray level of Figure 3.12, page 91 Different number of blocks used in this research Results of measurement values of the original images Correlation results of the transformed image 1 for all cases Correlation results against key length for image 1 of all cases Correlation results of case 1 Correlation results of the encrypted image 1 for all cases Results comparison between the Blowfish algorithm alone and the combination technique based on correlation test Correlation results against key length of the encrypted image 1 for all cases Entropy results of the encrypted image 1 against number of blocks for all cases with different key lengths

14 17 54 60 61 76 81 81 83 85 86 92 103 105 108 110 111 113 114 115 117 118 120 122 124 125

4.10 Results of entropy of the encrypted image1 versus key length for all cases 4.11 Standard deviation values against number of blocks with different key lengths 4.12 Results of standard deviation versus key length 4.13 The percentage of similarity between the original image and retrieved one 4.14 Two cases to test the impact of the insertion data of the encrypted images

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4.15 Results of correlation and entropy values with and without insertion data 4.16 Results of insertion data of case 1 4.17 Results of insertion data of case 2 4.18 Comparison results of correlation and entropy values of the original images and recovered ones 5.1 5.2 5.3 Correlation and entropy values of image1, encrypted by commercial algorithms Correlation and entropy values of image1, encrypted by commercial available algorithms preceded by the proposed algorithm Correlation and entropy values of commonly used encryption algorithms in Literature when applied to the image of Figure 5.3

126 127 128 130 138 138 140

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LIST OF FIGURES

1.1 1.2 1.3 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

General block diagram of the proposed technique Symmetric key algorithms A block diagram of the proposed technique versus Blowfish algorithm Image pixels Public key encryption and decryption model A simple model of symmetric key encryption Model of symmetric key cryptosystem Electronic Code Book (ECB) mode encryption Cipher Block Chaining (CBC) mode encryption Cipher Feedback (CFB) mode encryption Output Feedback (OFB) mode encryption An illustration of DES algorithm Rounds structure of the Blowfish encryption An illustration of AES_Rijndael algorithm Structure of MARS algorithm An example of an image histogram General block diagram of the transformation and encryption An overview model of the proposed technique at the sender side An overview model of the proposed technique at the receiver side The transformation process Encryption process using the Blowfish with and without transformation The horizontal correlation of image data The vertical correlation of image data The diagonal correlation of image data The opposite diagonal correlation of image data The correlation between variables for all directions Histogram of original and encrypted images The color value of pixel representation Mixing data at the sender side Extracting data at the receiver side Part of a ciphered image data without insertion

4 5 7 16 24 25 26 28 28 29 29 32 34 38 41 62 68 70 70 72 77 80 82 84 85 87 90 91 95 96 98

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3.16 3.17 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 5.1 5.2 5.3 5.4 5.5

Part of a ciphered image data with insertion Illustration of the decryption and retransformation processes The parts of the proposed model The original images (image 1 and image 2) used in the experiment Results of the transformed image 1 for all cases by using 8 bytes key, 16 bytes key and 32 bytes key Correlation values against number of blocks of the transformed image 1 Correlation values against key length of image 1 for all cases Results of encryption by using 30 30 blocks Correlation value of case 1 Correlation values against number of blocks with different key lengths Correlation values against key length of the encrypted image1 for all cases Entropy values of the encrypted image 1 against number of blocks for all cases with different key lengths Entropy values of the encrypted image 1 versus key length for all cases Standard deviation values against nu