17 New Steganography Technique with Symmetric Cryptography Swati Gupta, PG Student, Department of CSE, SSSITS, Sehore, India Gajendra Singh, Head, Department of CSE &IT, SSSITS, Sehore, India Ravindra K Gupta, Department of CSE & IT, SSSITS, Sehore, India ABSTRACT This paper describes about cryptography and a short survey on steganography techniques. We also mention the strong and weak points of these techniques briefly. Steganography is a science dealing with the hiding of the secured information in a harmless signal. An image, audio or video files may be used to embed the information. For image steganography, binary, gray scale or color images may be used as cover-images for hiding the secret data. In this paper a novel information hiding approach has been proposed in spatial domain, to improve Imperceptibility, efficiency and Security. The proposed approach expected result in less difference between the cover and stego image, high efficiency high Peak signal-to-noise (PSNR) value and make it much harder for the steganalysis algorithm to detect the hidden information. Keywords Steganography, Security, Encryption, Decryption, Internet. I. INTRODUCTION Cryptography is the practice and study of hiding information. In today s environment, cryptography is considered a branch of both mathematics and computer science, and is affiliated closely with information theory, computer security, and engineering. Cryptography is used in technologically advanced applications, including areas such as the security of ATM cards, computer passwords, and electronic commerce, which all depend on cryptography. Cryptography has long been of interest to intelligence gathering and law enforcement agencies. There has historically been a history of controversial legal issues surrounding cryptography. Encryption refers to the scrambling of information so that the original message can not be determined by unauthorized recipients. An encryption algorithm is applied to the message, referred to as the plaintext, and a key to produce cipher text, which ideally appears to be random bits. A decryption algorithm converts the cipher text back into plaintext, but only if given the correct key. Conventional, or symmetric, algorithms use the same key for both encryption and decryption. Public key algorithms use paired keys, one for encryption and another for decryption. Keys are the fundamental essential element in generating modern cipher text. A string of bits used widely in cryptography, allowing people to encrypt and decrypt data; a key can be used to perform other mathematical operations as well. Given a cipher, a key determines the mapping of the plaintext to the cipher text. The key to a particular cryptosystem is some value which, when applied to cipher text, allows the encrypted message to be decrypted and when applied to plaintext encrypts it. It is important to note that in the study of cryptography one talks about the lengths of keys in terms of bits. Messages, too, can be encrypted in n-bit blocks. The longer a key is the more difficult it is to break the encrypted message. There are two type of cryptography technique is available which is following Symmetric Cryptography Technique Asymmetric Cryptography Technique Symmetric cryptography technique encrypt and decrypt the message with the same key. This method of encryption is also called single-key, or symmetric encryption whereas Asymmetric cryptography technique encrypts the message with private key and decrypts the message with public key. With advancements in digital communication technology and the growth of computer power and storage, the difficulties in ensuring individuals privacy become increasingly challenging. The degrees to which individuals appreciate privacy differ from one person to another. Various methods have been investigated and developed to protect personal privacy. Encryption is probably the most obvious one, and then comes steganography. Encryption lends itself to noise and is generally observed while steganography is not observable. The term steganography refers to the art of covert communications [1].The aim of steganography is to hide information into a cover media, such as digital image, audio and video. Among evaluation criterions for steganography, the most important are imperceptibility and embedding capacity, that is to say, the stego media should be visually and statistically similar to the corresponding cover media under certain payload. Certainly, these two properties are contradictory. On the other hand, steganalysis aims to discover the existence of hidden secret information in the stego media. Universal blind detection is an important method in image forensics, and the essence of it is a statistical classified problem of
18 original image and stego image. In addition, the focus is finding some effective features to classify the two classes of images. According to the embedding positions, steganography is generally categorized into spatial and transform domain methods. Least-significant-bit substitution (LSB) [1], only the LSB plane of the cover image is overwritten with the information bits, is a wellknown and large capacity spatial method. The secret information is often encrypted before embedded, so it can be seen as random distributed bit stream of 0 and 1. Thus, LSB replacement happening to the whole image will produce structural asymmetry, which can be analyzed using histogram analysis such as the Chi-squared attack [2] or regular/singular groups (RS) analysis [3]. II. RELATED WORK Steganography is the science that involves communicating 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, thus the goal here is always to conceal the very existence of the embedded data [9]. In [1] I have observed that authors propose an approach for Image steganography based on LSBusing X-box mapping where they have used several Xboxes having unique data. The embedding part is done by Steganography algorithm where they use four uniquexboxes with sixteen different values (represented by 4-bits) and each value is mapped to the four LSBs of the cover image. This mapping provides sufficient security tothe payload because without knowing the mapping rules no one can extract the secret data (payload).the growth of high-speed computer networks and that of the Internet, in particular, has increased the ease of Information Communication. Ironically, the cause for the development is also of the apprehension - use of digital formatted data. In comparison with Analog media, Digital media offers several distinct advantages such as high quality, easy editing, high fidelity copying, compression etc [11]. But this type advancement in the field of data communication in other sense has hiked the fear of getting the data snooped at the time of sending it from the sender to the receiver [12]. So, Information Security is becoming an inseparable part of Data Communication. In order to address this Information Security Steganography plays an important role. Steganography is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message [13]. In [2] we have observed that a technique for image steganography based on Huffman Encoding is presented. In which two 8 bit gray level image of size M X N and P X Q are using as a cover image and secret image respectively. Huffman Encoding is performing over the secret image/message before embedding and each bit of Huffman code of secret image/message is embedded inside the cover image by altering the least significant bit (LSB) of each of the pixel's intensities of cover image. The size of the Huffman encoded bit stream and Huffman Table are embedding inside the cover image, so that the Stego-Image becomes standalone information to the receiver. Image steganography is a method of concealing information into a cover image to hide it. Least Significant-Bit (LSB) based approach is most popular steganographic techniques in spatial domain due to its simplicity and hiding capacity [10]. In [3] secret sharing refers to a method of distributing a secret among a group of participants, each of whom is allocated with a share of the secret. The participant s shares are used to reconstruct the secret. Single individual participants share is of no use. The reversible image sharing approach and threshold schemes are used achieve the novel secret color image sharing. The secret color image pixels will be transformed to many notational system. The reversible polynomial function will be generated using (t-1) digits of secret color image pixels. Secret shares are generated with the help of reversible polynomial function and the participant s numerical key. The secret image and the cover image is embedded together to construct a stego image. The reversible image sharing process is used to reconstruct the secret image and cover image. The secret is obtained by the lagrange s formula generated from the sufficient secret shares. Quantization process is applied to improve the quality of the cover image. Peak signal to noise ratio is applied to analyze the quality of the stego images. The simulation results show that the secret and cover are reconstructed without loss[3].security, the most common word uttered by any man, any device, any peripheral since past two centuries. Protection from malicious sources has become a part of the invention or the discovery cycle. Myriad methods of protection are used ranging from a simple authentication password to most cryptography algorithms for protecting the extreme sensitive or confidential data. In [4]we have analyzed that author proposes three indigenous methods as a variant of Cipher Block Chaining (CBC) mode for image encryption by considering three different traversing path (Horizontal, Vertical and Diagonal). In method one simple Raster Scan has been employed to scramble the confidential Image called Horizontal Image Scrambling (HIS). Method two is a variant of method one called Vertical Image Scrambling (VIS), here traversing path would be top to bottom left to Right. Third method employs diagonal traversing path called Diagonal Image Scrambling (DIS). Later Image Steganography has been adapted to send these Scrambled Images in an unnoticeable manner. In [5] a tutorial review of the steganography techniques appeared. Various image steganography techniques have been proposed. In this we investigate of founded
19 steganography techniques and steganalysis techniques. we state a set of criteria to analyze and evaluate the strengths and weaknesses of the previous techniques. The leastsignificant bit (LSB) insertion method is the most common and easiest method for embedding messages in an image with high capacity, while it is detectable by statistical analysis such as RS and Chi-square analyses. In [3] authors propose a novel LSB image steganography algorithm that can effectively resist image steganalysis based on statistical analysis. In [6] focused on the combination of cryptography and steganography methods and a new technique Metamorphic Cryptography has suggested. The message is transformed into a cipher image using a key, concealed into another image using steganography by converting it into an intermediate text and finally transformed once again into an image. The complexity of cryptography does not allow many people to actually understand the motivations and therefore available for practicing security cryptography. Cryptography process seeks to distribute an estimation of basic cryptographic primitives across a number of confluences in order to reduce security assumptions on individual nodes, which establish a level of fault-tolerance opposing to the node alteration. In a progressively networked and distributed communications environment, there are more and more useful situations where the ability to distribute a computation between a number of unlike network intersections is needed. The reason back to the efficiency (separate nodes perform distinct tasks), fault-tolerance (if some nodes are unavailable then others can perform the task) and security (the trust required to perform the task is shared between nodes) that order differently. Hence, in [7] described and reviewed the different research that has done toward text encryption and description in the block cipher. Moreover, in this suggests a cryptography model in the block cipher. There are many security issues in data communication. Cryptography is a substantially safe method to provide protection in data receiving and sending. In [8]expressed a novel algorithm of data hiding using cryptography named as ASK algorithm. Sensitive data is hided in a color image using cryptography. This shows how data can be send using a color image without ignorance of third party. Algorithm described a method for vanishing data in a color image. Problem Analysis: -In this section I have discussing over some issues which is observed during study of the previous research. III. PROPOSED CONCEPT The purpose of proposed cryptosystems is not to provide perfect or risk-free security. Rather, the purpose of cryptography-based security is to protect information resources by making unauthorized collection of the information or tampering with the information costly than the existing potential value that might be gained. Good proposed steganography, when properly implemented and used, makes attempts to violate security cost-prohibitive. To a computer, an image file is simply a file that shows different colors and intensities of light on different areas of the image. Wewill present an image in the form of matrix of pixels. The method will use in this research will be the logical operation like XOR and Circular Shift using a color key along with the proposed encryption process. The ASCII value of each character of the message is taken into account to perform manipulations to produce the cipher image. The cipher image is then concealed using a cover image using Steganography technique to obtain another image which is the final image. This image is sent to the receiver through the network. The receiver obtains the image, decrypts it to obtain the intermediate image and analyses this image with the cover image to reconstruct the cipher image. This cipher image is once again decrypted to obtain the original message. Figure 1 is shown the block diagram of proposed steganography technique at sender side. Similarly figure 2 is shown the receiver side block diagram of proposed steganography technique. Input Original Image Pixel Reader Binary Reader Proposed Encryption Key Input Stego Image LSB Reader LSB Excluder Ciphered Image Cover Image (I X J) Embedding (LSB) Cipher image Cipher Value Output Original Image Cover Image (I X J) Output (I X J) Stego Image Figure 1: Block diagram of proposed steganography technique model at sender end Key Proposed Decryption Binary Reader Figure2: Block diagram of proposed steganography technique model at receiver end Pixel Reader
20 IV. RESULTS The performance of the proposed steganography technique is analyzed in detail. We discuss the analysis of the proposed technique including some important ones like the PSNR and efficiency in terms of time and CPU utilization. Some experiments will carry to prove the efficiency of proposed technique. The measurement of the quality between the cover image f and stego-image of size M X N is done using PSNR (Peak Signal to Noise Ratio) value and the PSNR is defined as: PSNR = 10 x log(255 2 /MSE) N 1N 1 where, MSE = (f(x, y) g(x, y)) / N x= 0 y= 0 2 2 f(x, y) and g(x, y) means the intensity value of pixel at position (x, y) of the cover image and stego image respectively. The PSNR is expressed in db. Larger PSNR indicates the higher the image quality i.e. thereis only little difference between the cover-image and the stegoimage. Onthe other hand, a smaller PSNR means there is huge distortion between the cover-image and the stego image.the performance will be measure in terms of execution time, higher execution time will be causes of lower performance and lower execution will be causes of higher performance. Similarly CPU utilization and memory utilization is another important factor to calculate performance of the technique. Low execution will be the causes of higher CPU utilization and higher execution time will be the causes of lower CPU utilization. Memory utilization can be varying and it will depend upon the structure of the technique if complex structure wills causes of lower memory utilization. Expected outcome of the proposed technique are presented in table 1. This table show comparative analysis of the proposed technique. TABLE 1 Expected analysis of proposed steganography technique Parameters PSNR Performance CPU Utilization Throughput V. CONCLUSION Proposed Technique With the rising demand of the encryption strength, most governments have not satisfied with the current several cryptographic algorithms now, they continuous research on the new stegenography algorithms. However, it is difficult to evaluate the specific algorithm, they must consider many factors: security, the features of algorithm, the PSNR and complexity of time and space, etc. so research on the time-consuming of algorithm is one of the important respects [15]. In the past, evaluating timeconsuming of algorithm usually through comparing its time complexity, while this research proposing a new steganography technique with various evaluation parameters to measure the performance of the proposed technique. Besides, it takes full account of the key length of each algorithm. The results also indirectly reflect the motivation of developing image cryptographic algorithms. REFERENCES [1] Amitava Nag, SaswatiGhosh, SushantaBiswas, DebasreeSarkar, ParthaPratimSarkar An Image Steganography Technique using X-Box Mapping IEEE-International Conference On Advances In Engineering, Science And Management (ICAESM - 2012) March 30, 31, 2012 [2] RigDas and ThemrichonTuithung A Novel Steganography Method for Image Based on Huffman Encoding IEEE 2012 [3] L.JaniAnbarasi and S.Kannan Secured Secret Color Image Sharing WithSteganography IEEE 2012 [4] RengarajanAmirtharajan\ Anushiadevi.R2, Meena.y2, Kalpana. y2 and John BoscoBalaguru Seeable Visual But Not Sure of It IEEE-International Conference On Advances In Engineering, Science And Management (ICAESM -2012) March 30, 31, 2012 [5] G.KarthigaiSeivi, Leon Mariadhasan, K. L. Shunmuganathan Steganography Using Edge Adaptive Image IEEE International Conference on Computing, Electronics and Electrical Technologies [ICCEET] 2012 [6] Thomas LeontinPhiljon. andvenkateshvararao. Metamorphic Cryptography - A Paradox between Cryptography and Steganography Using Dynamic Encryption IEEE-International Conference on Recent Trends in Information Technology, ICRTIT 2011 [7] Ashwak M. AL-Abiachi, Faudziah Ahmad and Ku Ruhana A Competitive Study of Cryptography Techniques over Block Cipher UKSim 13th IEEE International Conference on Modelling and Simulation 2011 [8] Abhishek Gupta, SandeepMahapatra and, Karanveer Singh Data Hiding in Color Image Using Cryptography with Help of ASK Algorithm 2011 IEEE [9] Guy-Armand Yandji, LuiLianHao, Amir- EddineYoussouf and Jules Ehoussou RESEARCH
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