International Journal of Computer Engineering & Applications, Vol. II, Issue I/III IMAGE STAGENOGRAPHY

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1 IMAGE STAGENOGRAPHY Anand Paratap Singh 1, Esh Narayan 2 1 Master of Technology in IFTM University, Moradabad 1,2, Computer Science & Engineering 2 Dept. of Computer Science and Engineering PRABHAT ENGG COLLAGE KANPUR (UP) ABSTRACT: Stagenography is the art of science that involves the communication of secret data in an appropriate multimedia carrier, e.g., image, audio, and video files. It comes under the assumption that if the feature is visible, the point of attack is evident, that the goal is always to conceal the very existence of the embedded data. Steganography has various useful applications. However, like any other art it can be use full for ill intentions. It has been propelled to the forefront of current security methods by the remarkable growth in computational power, the increase in security awareness by, e.g., individuals, groups, agencies, government and through intellectual pursuit. Steganography s ultimate objectives, which are undetected, robustness (resistance to various image processing methods and compression) and capacity of the hidden data, are the main factors that separate it from related techniques such as watermarking and cryptography. This paper provides a state-of-the-art review and analysis of the different existing methods of steganography along with some common standards and guidelines drawn from the literature. This paper concludes with some recommendations and advocates for the object-oriented embedding mechanism. Stage analysis, which is the science of attacking steganography, is not the focus of this survey but nonetheless will be briefly discussed. Keywords- Digital image steganography; spatial domain; frequency domain; adaptive steganography; security 1. INTRODUCTION Steganography is the art of hiding information in ways that prevent the detection of hidden messages, this definition gives by the researchers Neil F. Johnson and Sushil Jajodia at George Mason University in Fairfax. Where cryptography encodes a message so it cannot be understood, steganography hides a message so its mere existence is not known. Steganography is the science and art of writing hidden messages in such a way that no one apart from the intended recipient knows the existence of the message. Recently, many digital techniques have been developed that perform steganography on electronic media, most notably sound and image files. The outcome of this project is to create a tool that can effectively hide a message inside a digital image file. Steganography is a way of protecting information, same as to cryptography and watermarking. While watermarking ensures message integrity and cryptography scrambles a message, steganography hides it. The concept of steganography has been around since Ancient Greece, yet only in the past couple of decades has it been applied to digital information. Current digital techniques can provide reasonable security for the hidden message, but often leave marks that suggest the cover has been tampered with. Most of these marks are caused by the message being embedded into the cover without any regard to the cover s original content. Therefore, it is highly likely that if the original content was taken into account it would become significantly more difficult to discover whether steganography has been used. It would be 128

2 interesting to find out whether doing this makes it more complex Objective Objective of this project is to develop software, namely Steganos that can be used for steganography and stage analysis. An ideal steganography system should be unobtrusive, robust- to all types of image processing techniques, unambiguous, should not rely on the secrecy of the algorithm. My Project is not only a steganography system it could and should be extended to incorporate watermarking in multimedia. 1.2 problem statement The whole scope of problem can be stated as: a. Studying the various steganography and stage analysis methods. b. The Individual modules for driving with the core of the steganography engine i.e. the algorithms. c. Implementation of the Reverse process i.e stage analysis for some popular methods. d. Designing a interactive GUI for the user. e. Integrating all the individual modules so that the user could hide his/her data(any kind) i.e. any kind of data by choosing an algorithm from the algorithm library within a cover file. f. Testing for various kinds of multimedia files i.e. png images, tiff images, jpeg images both 8bit (grayscale) and 24bit (color images) and for wav files. 2. LITERATURE SURVEY Steganography comes from Greek and means covered writing. The ancient Greeks wrote text on wax-covered tablets. To pass a hidden message, a person would scrape off the wax and write the message on the underlying wood. He/she would then once again cover the wood with wax so it appeared unused. Many developments in steganography occurred during World War II. This included the development of invisible inks, microdots, and encoded messages. One known message sent by a German spy was: Apparently neutral s protest is thoroughly discounted and ignored. Is man hard hit. Blockade issue affects pretext for embargo on by-products, ejecting suet and vegetables oils. Extracting second letter in each word reveals: Pershing sails from NY June Steganography has a long history, which can be traced back to Ancient Greece. In his Histories, Herodotus (c B.C.) tells how the head of a trusted slave was shaved and tattooed with a message. 2 The message was hidden after the hair had regrown, at which time the slave could travel without arousing any enemy suspicion. However, it is easy to see that once the enemy is aware of this method of hiding information, they can simply shave the head of every slave that passes through their territory, defeating the system. This modern steganography can be broken up into three categories: Pure steganography is hiding where no information other than the hiding technique is required, as this is sufficient knowledge to be able to retrieve the hidden message. The latter two categories, secret key and public key steganography, rely on the passing of a key (or keys) without which the hidden information cannot successfully be extracted. Most steganographic software available implements the secret key approach due to the facts that pure steganography is simple to break once you know the method and public key steganography is considered to be theoretically impossible. Despite the many incarnations of steganography methods and 129

3 the development over time, the result is still the same. A message is transmitted inside some sort of cover in such a way that a third party looking at the cover is not aware that the hidden message even exists. Algorithm Pure steganography No key is necessary E: Ca x M -> Ca D: Ca -> M Relies on the secrecy of the method Example:Using the first character in a letter to hide the secret message Null cipher (unencrypted message): News Eight Weather: Tonight increasing snow. Unexpected precipitation smothers eastern towns. Be extremely cautious and use snowtires especially heading east. The highways are knowingly slippery. Highway evacuation is suspected. Police report emergency situations in downtown ending near Tuesday. First letter of each word: Newt is upset because he thinks he is President. Secret key steganography Algorithm Uses a secret stego-key: sender and receiver share stego-key E: Ca x (K x M) -> Ca D: Ca x K -> M Example Encrypt data using shared secret key before hiding within the carrier Public key steganography Algorithm Uses two keys: public/private key combo Public key encryption E: Ca x (U x M) -> Ca D: Ca x R -> M Private key encryption E: Ca x (R x M) -> Ca D: Ca x U -> M Various programs offered today Freeware/Shareware include: Hide and Seek: hides data in LSB of GIF & BMP Camouflage: hides data (ex: MP3 s) by encrypting and then appending the data to the end of a file S-Tools: LSB color reduction, then inserts additional data to hide color modification Flaws with Steganography Fig Features of JAVA Platform Independent The concept of Write-once-run-anywhere (known as the Platform independent) is one of the important key feature of java language that makes java as the most 130

4 powerful language. Not even a single language is ideal to this feature but java is closer to this feature. The programs written on one platform can run on any platform provided the platform must have the JVM. Simple There are various features that makes the java a simple language. Programs are easy to write and debug because java does not use the pointers explicitly. It is much harder to write the java programs that can crash the system but we can not say about the other programming languages. Java provides the bug free system due to the strong memory management. It also has the automatic memory allocation and deal location system. Object Oriented To be an Object Oriented language, any language must follow at least the four characteristics. Inheritance Encapsulation Polymorphism Dynamic binding Robust Java has the strong memory allocation and automatic garbage collection mechanism. It provides the powerful exception handling and type checking mechanism as compare to other programming languages. Compiler checks the program whether there any error and interpreter checks any run time error and makes the system secure from crash. All of the above features makes the java language robust. Distributed The widely used protocols like HTTP and FTP are developed in java. Internet programmers can call functions on these protocols and can get access the files from any remote machine on the internet rather than writing codes on their local system. Portable The feature Write-once-runanywhere makes the java language portable provided that the system must have interpreter for the JVM. Java also has the standard data size irrespective of operating system or the processor. This feature makes the java a portable language. 3. FORMULATIONS AND PRESENTATION OF THE PROBLEM 3.1. Data flow diagram Hiding the secret text Cover image Bit LSB Algorith m bits Stego image bit bit Plain text Key 131

5 Fig retrieving the hidden text Stego image bit LSB algo bit Plain text bit 3.2. Technology Used Fig key object oriented code and an extensive usage of objects, classes, methods etc has been done. The user with the help of the GUI provided to him selects the input files i.e. the cover and the data file. There is a separate file reading module which reads the cover file(which could be an image(.png, The Steganos has been developed in java using JDK1.5.0.The GUI was developed using Forte for Java CE. For editing photos for testing the program we used Adobe Photoshop. The whole Project was developed using Pentium IV 1.7 MHz and with proper graphics support and Memory Of 128MB RAM. The project is totally platform independent since it is developed by using java foundation classes (JFC).Faster processors are recommended for better results since a lot of computation is involved..jpeg,.tiff ),after the cover file is read the file where data is collected System Architecture The figure shows the overall system architecture. Some standard classes have been used from the java library. The architecture is quite simple. It s totally 132

6 of the code has strictly adhered to the Object-Oriented philosophy. This enabled a highly modular development approach and extensive code reuse. Modules developed are highly coherent and loosely coupled. Each module is able to inherit from any other module when needed and also instantiate any class of any other module. The user can hide data of any kind of his/her choice although of some limited size. Algorithm library allows choosing from high capacity algorithms to highly robust algorithms General Method of Steganography What we do in Steganography is we have a cover image where we hide data using an embedding function like the algorithms which we use by using a key. Fig: Software as the file resource provided by the user. There is no limitation to the kind of file which the user can hide and retrieve using this software and we support all kind of data file to be hide although there is limitation to the size of data that can be hidden in a cover file.the file reading module interacts the GUI Manager and the Algorithm Library to read the file from the hard disk and the Core Steganos Engine. The Core Steganos Engine takes the help of the Authentication Module and the Key Generation facility to implement the camouflage and retrieval of data. Proper error messages are generated to guide the user through the whole process of using the software if he goes wayward from the way the software should function Key Features The project has various unique features that enhance the functionality. The architecture Fig Diagram showing the various method of steganography Lower Order LSB Algorithm 133

7 The most widely used technique to hide data, is the usage of the LSB. Although there are several disadvantages to this approach, the relative easiness to implement it, makes it a popular method. To hide a secret message inside a image, a proper cover image is needed. Because this method uses bits of each pixel in the image, it is necessary to use a lossless compression format, otherwise the hidden information will get lost in the transformations of a lossy compression algorithm. When using a 24 bit color image, a bit of each of the red, green and blue color components can be used, so a total of 3 bits can be stored in each pixel. Thus, a pixel image can contain a total amount of bits ( bytes) of secret data. For example, the following grid can be considered as 3 pixels of a 24 bit color image, Using 9 bytes of memory: ( ) ( ) ( ) When the character A, which binary value equals , is inserted, the following grid results: ( ) ( ) ( ) This method uses the least significant bits (LSB) of the bytes of the cover to hide the message. A computer s file is made out of ones and zeros, called bits. A byte is a group of bits. Every type of file has a different format. On average, only half of the bits in an image will need to be modified to hide a secret message using the maximal cover size. The resulting changes that are made to the least significant bits are too small to be recognized by the human eye, so the message is effectively hidden. While using a 24 bit image gives a relatively large amount of space to hide messages, it is also possible to use a 8 bit image as a cover source. Because of the smaller space and different properties, 8 bit images require a more careful approach. Where 24 bit images use three bytes to represent a pixel, an 8 bit image uses only one. Embedding process: least significant bit substitution(lsb Image) for i = 1,...,l(c) do si ci end for for i = 1...,l(m) do compute index ji where to store ith message bit sji cji mi end for Extraction process: least significant bit substitution for i = 1,...,l(M) do compute index ji where the ith message bit is stored mi 134

8 =LBS(C IJ ) End for Randomized Algorithm In case, the sender uses all cover-elements for information transfer, starting at the first element. Since the secret message will normally have less bits than l(c), the embedding process will be finished long before the end of the cover. In this case, the sender can leave all other cover elements unchanged. This can, however, lead to a serious security problem: the first part of the cover will have different statistical properties than the second part, where no modifications have been made. The embedding process the changes far more elements than the transmission of the secret would require. Therefore the probability that an attacker will suspect secret Communication increases. A more sophisticated approach is the use of a pseudorandom number generator to spread the secret message over the cover in a rather random manner; a popular approach is the random interval method.if both communication partners share a stego-key k usable as a seed for a random number generator, they can create a random sequence k1,..., kl(m) and use the elements with indices for information transfer. Thus, the distance between two embedded bits is determined pseudo randomly. Since the receiver has access to the seed k and knowledge of the pseudorandom number generator, he can reconstruct ki and therefore the entire sequence of element indices ji. This technique is especially efficient. 5. RESULTS AND IMPLEMENTATION 5.1 Testing Objectives Testing is a process of executing a program with the intent of finding an error. A good test case is one that has a high probability of finding an as-yet undiscovered error. A successful test is one that uncovers an asyet-undiscovered error. The above objectives imply a dramatic change in viewpoint. They move counter to the commonly held view that a successful test is one in which no errors are found. Our objective is to design tests that systematically uncover different classes of errors and do so with a minimum amount of time and effort. If testing is conducted successfully (according to the objectives stated above), it will uncover errors in the software. Testing cannot show the absence of defects, it can only show that software errors are present. 5.2 Testing Techniques The techniques followed throughout the testing of the system are as under Black- Box Testing Black box testing focuses on the functional requirements of the software. That is, Black Box testing enables the software engineer to derive sets of input conditions that will fully exercise all functional requirements for a program. Black Box Testing is not an alternative to white-box techniques. Rather, it is a complementary approach that is likely to uncover a different class of errors than white-box methods. Black-Box Testing attempts to find errors in the following categories: 1. Incorrect or missing functions. 2. Interface errors. 3. Errors in data structures or external data base access. 4. Performance errors. 135

9 5. Initialization and termination errors. Unlike White Box Testing, which is performed early in the testing process, Black Box Testing tends to be applied during later stages of testing. Because Black Box Testing purposely disregards control structure, attention is focused on the information domain. White-Box Testing White Box Testing knowing the internal workings of a product tests can be conducted to ensure that internal operations are performed according to specifications and all internal components have been adequately exercised. Using white box testing methods the test cases that can derived are: (1) All independent paths with in a module have been exercised at least once. (2) Exercise all logical decisions on their true and false sides. (3) Execute all loops at their boundaries and within their operational bounds. (4) Exercise internal data structures to ensure their validity. Control Structure Testing 1) Condition Testing Condition testing is a test case design method that exercises the logical conditions contained in a program module. If a condition is incorrect then at least one component of the condition are incorrect Therefore types of errors in a condition including the following? Boolean operator error Boolean variable error Boolean parenthesis error Relational operator error Arithmetic expression error 2) Loop Testing Loops are the corner stone for the vast majority of all algorithms implemented in software. Loop testing is a white-box testing technique that focuses exclusively on the validity of loop constructs. 3) Control Testing The dataflow testing method selects test paths of a program according to the location of definitions and uses of variables in the program. In this testing approach, assume that each statement in a program is assigned a unique statement number and that each function does not modify its parameters or global variables. It is useful for selecting test paths of a program containing nested if and loop statement. This approach is effective for error detection. However, the problems of measuring test coverage and selecting test paths for data flow testing are more difficult than the corresponding problems for condition testing. Unit Testing Unit testing focuses verification efforts on the smallest unit of software design. It is white box oriented. Unit testing is essentially for verification of the code produced during the coding phase and hence the goal is to test the intemallogic of the module. Others consider a module for integration and use only after it has been unit tested satisfactorily. The module interface is tested to ensure that information properly flows in and out of program. Local data structure is examined to ensure that data stored temporarily maintain its integrity. Boundary conditions are tested to ensure that modules operate properly at boundary limits of processing. All independent paths are exercised to ensure all statements in a module have been executed at least once. 136

10 Integration Testing Integration testing focuses on design and construction of the software architecture. For example: - We followed a systematic technique for constructing the program structure that is "putting them together"- interfacing at the same time conducting tests to uncover errors. We took unit tested components and build a program that has been dictated by design. 6. CONCLUSION AND FUTURE SCOPE We have implemented about 6 algorithms for image steganography 3 variants of audio steganography, and one algorithm for Steganalysis.Screen shots display the output of the software applied for different cases. There is no dearth to the type of information that the user can hide. Only exception is there to the amount of information that he can hide. Comparative analysis of the various algorithms Steganography, especially combined with cryptography, is a powerful tool which enables people to communicate without possible eavesdroppers even knowing there is a form of communication in the first place. The methods used in the science of steganography have advanced a lot over the past centuries, especially with the rise of the computer era. Although the techniques are still not used very often, the possibilities are endless. Many different techniques exist and continue to be developed, while the ways of detecting hidden messages also advance quickly. Since detection can never give a guarantee of finding all hidden information, it can be used together with methods of defeating steganography, to minimize the chances of hidden communication taking place. Even then, perfect steganography, where the secret key will merely point out parts of a cover source which form the message, will pass undetected, because the cover source contains no information about the secret message at all. In the near future, the most important use of steganographic techniques will probably lie in the field of digital watermarking. Content providers are eager to protect their copyrighted works against illegal distribution and digital watermarks provide a way of tracking the owners of these materials. Although it will not prevent the distribution itself, it will enable the content provider to start legal actions against the violators of the copyrights, as they can now be tracked down. Steganography might also become limited under laws, since governments already claimed that criminals use these techniques to communicate. ACKNOWLEDGEMENTS 137

11 I would like to add few heartfelt words for the people, who were part of this project in numerous ways, people who gave support in completing this report. Completion of the project would not have been possible without mutual efforts and integrated thoughts. I wish to express my gratitude and hearty appreciation to my Project Guide and Mentor Prof. Bharat Agarwal for providing a self-learning and congenial environment and for his continuous encouragement and enthusiastic guidance in the successful completion of the project work. REFERENCES [1] N.F. Johnson and S. Jajodia, Exploring steganography: Seeing the unseen, IEEE Computer, 31(2)(1998) [2] D. Frith, Steganography approaches, options, and implications, Network Security, 2007(8)(2007)4-7 [3] H. Farid, A Survey of image forgery detection, IEEE Signal Processing Magazine, 26(2)(2009) [4] A. Cheddad, J. Condell, K. Curran and P. Mc Kevitt, A secure and improved self-embedding algorithm to combat digital document forgery, Signal Processing, 89 (12)(2009) [9] Johnson, N. F. S. D, Z., Information Hiding: Steganography [10] Katzenbeisser, S. P., A. P, Information Hiding Techniques [11]. Saxena P.C., Gupta J.P., Gupta N., Web Page Ranking Based on Text Content of Linked Pages, International Journal of Computer Theory and Engineering (IJCTE), vol. 2, no. 1, pp , Feb [12] Benjamin C. M., Fung Ke, Wang M.E., Large hierarchical document clustering using frequent itemsets, Proc. Third SIAM International Conference on Data Mining 2003, pp , [13] Borodin A., Roberts Gareth O., Rosenthal J.S., Tsaparas P., Finding Authorities and Hubs from link structures on the World Wide Web, Proc. 10th WWW Conference, Hong Kong, pp , [14] Borodin A., Roberts Gareth O., Rosenthal J.S., Tsaparas P., Link analysis ranking: algorithms, theory, and experiments, ACM Transactions on Internet Technology, vol. 5, no. 1, pp , [15] S. Butcher, Charles LA. Clarke. A. Index compression is good, especially for random access. In Proc. of the 16th ACM CIKM, pages , 2007 [16]Borodin A., Roberts Gareth O., Rosenthal J.S., Tsaparas P., Link analysis ranking: algorithms, [5] H. Nakamura and Q. Zhao, Information hiding based on image morphing, in: Proceedings of 22ndInternational Conference on Advanced Information Networking and Applications Workshops, AINAW March 2008, [6] Avedissian, L.Z," Understanding Testing Strategies. [7] C. J. S. B, Modulation and Information Hiding in Images, [8] Dorothy, E.R, D.K, Cryptography and Data Security 138