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A Cryptanalysis Methodology for the Reverse Engineering of Encrypted Information in Images Wright State University CORE Scholar Browse all Theses and Dissertations Theses and Dissertations 2009 A Cryptanalysis Methodology for the Reverse Engineering of Encrypted Information in Images Allan Anthony Rwabutaza Wright State University Follow this and additional works at: https://corescholar.libraries.wright.edu/etd_all Part of the Computer Engineering Commons, and the Computer Sciences Commons Repository Citation Rwabutaza, Allan Anthony, "A Cryptanalysis Methodology for the Reverse Engineering of Encrypted Information in Images" (2009). Browse all Theses and Dissertations. 975. https://corescholar.libraries.wright.edu/etd_all/975 This Dissertation is brought to you for free and open access by the Theses and Dissertations at CORE Scholar. It has been accepted for inclusion in Browse all Theses and Dissertations by an authorized administrator of CORE Scholar. For more information, please contact [email protected]. A CRYPTANALYSIS METHODOLOGY FOR THE REVERSE ENGINEERING OF ENCRYPTED INFORMATION IN IMAGES A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy By ALLAN ANTHONY RWABUTAZA M.S., Mathematics, Miami University, 2004, B.A., Mathematics, Berea College, 2002 ______________________________________________ 2009 Wright State University COPYRIGHT BY ALLAN ANTHONY RWABUTAZA 2009 2 WRIGHT STATE UNIVERSITY SCHOOL OF GRADUATES STUDIES November 20, 2009 I HEREBY RECOMMEND THAT THE DISSERTATION PREPARED UNDER MY SUPERVISION BY Allan Anthony Rwabutaza, ENTITLED A Cryptanalysis Methodology for The Reverse Engineering of Encrypted Information in Images BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy Nikolaos G. Bourbakis, Ph.D. Dissertation Director Arthur Ardeshir Goshtasby, Ph.D. Director, Computer Science and Engineering Ph.D. Program Joseph F. Thomas Jr., Ph.D. Dean, School of Graduate Studies Committee on Final Examination Nikolaos G. Bourbakis, Ph.D. (Committee Chairman) Soon Chung, Ph.D. Yong Pei, Ph.D. Arnab Shaw, Ph.D. Monish Chatterjee, Ph.D. 3 ABSTRACT Rwabutaza, Allan Anthony. Ph.D., Department of Computer Science & Engineering, Wright State University, 2009. A Cryptanalysis Methodology for the Reverse Engineering of Encrypted Information in Images. Security is an important issue related to the storage and communication of data and information. In data and information security, cryptography and steganography are two of the most common security techniques. On one hand, there is cryptography, which is the secret communication between two parties by message scrambling on the sender’s side and message unscrambling on the receiver’s side so that only the intended receiver gets the secret message. On the other hand, there is steganography, which is the hiding of information in a medium in such a way that no one other than the sender or the intended receiver realizes there is a hidden message. Successful reverse engineering of cryptography and steganography give cryptanalysis and steganalysis respectively. Cryptography and cryptanalysis constitute cryptology (or crypto) while steganography and steganalysis make up steganology (or stegano). This dissertation consists of three parts needed for a scientific study of a cryptanalysis problem. The first part lays out a comparative survey of various cryptology and steganology techniques by analyzing and comparing different methodologies using a set of predefined parameters. This part offers valuable knowledge on the state of the art techniques used on cryptanalysis. The second part proposes a new lossless synthetic stegano-crypto methodology that blends together five cryptography, steganography and compression techniques to form a single methodology for mutual information encryption and hiding in images. The methods that compose the synthetic methodology are SCAN Encryption, SCAN Compression, SCAN Steganography, 4 Least Significant Bit (LSB) Steganography and Regional Steganography with Segmentation. The synthetic methodology plays the role of a complex and difficult technique that we have to work on in an attempt to break it by using a reverse engineering approach. In the third part, a cryptanalysis attack against the proposed synthetic stegano-crypto methodology is presented in order for the important features (weak points) related to the method to be extracted and assist in the reverse engineering process of encrypted information in images. 5 Table of contents List of figures ............................................................................................................................ 12 List of tables ............................................................................................................................. 15 Acknowledgment ...................................................................................................................... 17 PART 1- A CRYPTOLOGY COMPARATIVE SURVEY ........................................................ 18 1. Introduction- Cryptology ....................................................................................................... 18 Basic Cryptology Concepts ................................................................................................... 18 2. Cryptography ........................................................................................................................ 20 2.1. Types of Cryptography ................................................................................................... 20 2.1.1. Symmetric Key Cryptography .................................................................................. 20 DES................................................................................................................................... 20 Triple-DES ........................................................................................................................ 21 AES................................................................................................................................... 21 IDEA ................................................................................................................................. 21 Blowfish ............................................................................................................................ 21 RC4 ................................................................................................................................... 21 CAST ................................................................................................................................ 22 GOST ................................................................................................................................ 22 SKIPJACK ........................................................................................................................ 22 2.1.2. Asymmetric Key Cryptography................................................................................. 22 Diffie-Hellman .................................................................................................................. 23 RSA .................................................................................................................................. 23 DSA .................................................................................................................................. 23 6 Elliptic Curve Cryptography .............................................................................................. 23 2.1.3. Hybrid Cryptography ............................................................................................... 24 2.2. Message Integrity in cryptography .................................................................................. 24 MD4 .................................................................................................................................. 24 MD5 .................................................................................................................................. 24 SHA-1................................................................................................................................ 25 RIPEMD ........................................................................................................................... 25 2.3. Authentication in cryptography ....................................................................................... 25 Digital Signature ............................................................................................................... 25 Digital Certificates ............................................................................................................ 26 2.4. Applications of Symmetric and Asymmetric cryptography ............................................. 26 2.4.1. Text Encryption ....................................................................................................... 27 Transposition ciphers......................................................................................................... 27 Substitution ciphers ........................................................................................................... 27 Z mod NZ ciphers ............................................................................................................. 27 Shift Transformation Ciphers ............................................................................................ 28 Linear Transformation Ciphers .........................................................................................
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