Steganography is the art of secret writing, where a message, file or image is concealed within another to hide its existence. There are many different algorithms that make use of diverse techniques and implementations to hide data in various forms of digital media. This paper will focus on the comparison of two image steganography algorithms, namely the F5 algorithm and YASS (Yet Another Steganographic Scheme).
The paper will first provide a brief overview of each algorithm and their respective implementations with their advantages and disadvantages. It will then proceed to compare the algorithms based on their type, cover image formats, embedding channels, use of stego keys, robustness and security.
Both the F5 algorithm and YASS were developed to embed secret messages within the JPEG image format. This image format is an example of lossy compression that makes use of the discrete cosine transform (DCT) (Cabeen & Gent, 1998: 1). Because both the F5 and YASS algorithms embed messages into JPEG images, it is first necessary to provide an overview of what happens during JPEG compression.
When a JPEG image is compressed, the color model is first transformed from the RGB model to the YCBCR model. This transformation is not always necessary but allows for higher compression rates at the same level of reliability (Fridrich, 2010: 22). Each channel of the image is then divided into 8 x 8 blocks of pixels as is shown in Figure 1 below. The chrominance signals (CBCR components) could be sub-sampled before this division into blocks as the human eye is less sensitive to changes in chrominance than luminance (Fridrich, 2010: 23).
Next, the pixel values of each block is shifted from the range [0,255] to a new range [-128, 127] that centre...
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...s about the security performance of an algorithm. They compared the highest detection accuracy rates that was achieved by the 4 detection algorithms for F5 and YASS and show the accuracy rates along with the bits per non-zero DCT coefficient for each algorithm. The diagram can be seen below in Figure 6.
Conclusion
Both the F5 and YASS algorithms are examples of JPEG steganography and each have their strengths and weaknesses. For both algorithms, researchers have proposed different ways in which the data embedded using the algorithms could be detected. Since their appearance, many variations of the two algorithms has been created that aim to improve aspects such as their embedding efficiency, robustness and security. Unfortunately, there will always be a trade off between the embedding capacity, robustness and security/undetectability of steganographic algorithms.
Murphy, S.D. 2004. “Steganography--the New Intelligence Threat.” Marine Corps War College, Marine Corps University, Marine Corps Combat Development Command. Quantico: VA. http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA520517 (accessed November 31, 3013).
describes the Contourlet transform and rotation-scale invariant texture representation. Section 4 contains the description of similarity measure for image retrieval. Simulation results in Section 5 will show the performance of our scheme. Finally,Section 6 concludes this presentation.
Every kind of digital file carries invisible ‘tags’. By taking a picture you can detect the
Encryption has a very long history,1 which can be traced back to about 1900 B.C. Cryptography was first used in the form of hieroglyphic inscription by an ...
Codes have been around for centuries ranging from wax, invisible ink, Morse code, the Enigma used by the Germans during World War II and now steganographic. Steganography is the latest form to insidiously hide information over the Internet without a trace of a file being altered. You are able to hide messages within images, voice or music. Steganography is an ancient method of hiding messages. Today messages are hidden in images and music. Steganography can be traced back to the ancient Greek who would write messages on tablets and cover them in wax. This made the tablets look blank and unsuspicious (Kolata, F4). Citizens of ancient civilizations would tattoo messages on their shaved heads. They would then let their hair grown in and travel across enemy lines to deliver the message (Seper, G1). During World War II the Allies placed a ban on flower deliveries with dates, crossword puzzles and even report cards (Kolata, F4) for fear of a message being hidden with in. Steganographers first alter their data by using encryption and then place the image into a pre-select image. Steganographers look for a piece of code that would be the least significant and look the least altered to the human eye (Kolata, F4), being as inconspicuousness and random as possible. This makes the messages undetectable unless you knew that there is a message hidden and you were able to crack the code.
Region of interest is an important feature provided by jpeg 2000 standard. The entire image is encoded as single entity by different fidelity constraints. This...
Steganography is basically made from two greek words steganos and grapter.steganos means covered and grapter means writing so steganography means “covered writing”.steganography is writing the secret message.The goal of steganography is to hide the text by installed messages in objects such as digital images, audio,video or text files.The other area of steganography is a copyright marking where the message is inserted to copyright over a document. steganography and watermarking portray routines to insert data straightforwardly into a bearer signal. Data stowing away in sound signs is increasing boundless significance for secure correspondence of data, for example, clandestine front line and managing an account exchanges by means of open sound
Therefore, verifying the authenticity of digital images has become a very important issue. JPEG is one of the most commonly used compression schemes in many practical applications. Therefore JPEG image forensics has attracted increasing attention recently. Typically, there are two significant properties available for forensic analysis. The first and the most obvious property are the blocking artifacts in the spatial domain. Due to the block-based processing in the lossy JPEG compression, the discontinuous pixels usually occur in the boundary between two adjacent 8 × 8 blocks.
For thousands of years cryptography and encryption have been used to secure communication. Military communication has been the leader of the use of cryptography and the advancements. From the start of the internet there has been a greater need for the use of cryptography. The computer had been invented in the late 1960s but there was not a widespread market for the use of computers really until the late 1980s, where the World Wide Web was invented in 1989. This new method of communication has called for a large need for information security. The internet allows people to communicate sensitive information, and if received into the wrong hands can cause many problems for that person.
As a part of under graduating course I presented my major project on JPEG Encoding and Decoding using MATLAB technology, which included going from a basic grayscale bitmap image all the way to a fully encoded file readable by standard image readers.
Symmetric cryptography, also known as secret key cryptography, has been in use for thousands of years in forms ranging from simple substitution ciphers(figures) to more complex developments. Be that as it may, improvements in science and the development of computing power have made it possible to make ciphers(figures) that are effectively unbreakable and secured. Symmetric frameworks are for the most part quick however are powerless so the key used to encrypt must be imparted to whomever needs to decrypt the message. The IBM-created figure DES has been generally utilized yet is presently toward the finish of its helpful life and is expected for substitution. Whatever figure designers use in their applications, it's vital to consider the
Nowadays when more and more sensitive information is stored on computers and transmitted over the Internet, we need to ensure information security and safety. Image is also an important part of our information .Therefore it’s very important to protect our image from unauthorized access.Security of multimedia information is used to protect the multimedia content...
Hlavac and J. Fojt?k [11], in 1998, proposed a new method for lossless image compression of grey-level images. The image is treated as a set of stacked bit planes. The compressed version of the image is represented by residuals of a non-linear local predictor spanning the current bit plane as well as a few neighbouring ones. Predictor configurations are grouped in pairs differing in one bit of the representative point only. The frequency of predictor configurations is obtained from the input image. The predictor, as adapts automatically to the image and is able to estimate the influence of neighbouring cells, copes even with complicated structure or fine texture. The residuals between the original and the predicted image are those that correspond to the less frequent predictor configurations. Efficiently coded residuals constitute the output image. Good results were obtained for binary images, grey-level cartoons and man-made
Digital representation provides better efficiency and accuracy of copying, storing and distributing content via the internet. This improvement of digital technology helped the data to easily duplicated and rapidly delivered to a big number of users with minimum expense. This technology has become the most popular way to distribute multimedia content. Digital Right Management (DRM) is a technology used by publishers, copyright holders to restrict the illegal media conception, copying and redistribution. But sometimes it is insufficient to protect the multimedia data. Here is the actual use of the digital watermarking technology. Watermarking is a technology in which a hiding a digital data inside the host signal. Thus it will help to verifying the authority or integrity of the host signal.