Showing papers on "Steganography published in 2008"

(Journal of Systems and Software, 81(1):150-158)A high quality steganographic method with pixel-value differencing and modulus function

Abstract: In this paper, we shall propose a new image steganographic technique capable of producing a secret-embedded image that is totally indistinguishable from the original image by the human eye. In addition, our new method avoids the falling-off-boundary problem by using pixel-value differencing and the modulus function. First, we derive a difference value from two consecutive pixels by utilizing the pixel-value differencing technique (PVD). The hiding capacity of the two consecutive pixels depends on the difference value. In other words, the smoother area is, the less secret data can be hidden; on the contrary, the more edges an area has, the more secret data can be embedded. This way, the stego-image quality degradation is more imperceptible to the human eye. Second, the remainder of the two consecutive pixels can be computed by using the modulus operation, and then secret data can be embedded into the two pixels by modifying their remainder. In our scheme, there is an optimal approach to alter the remainder so as to greatly reduce the image distortion caused by the hiding of the secret data. The values of the two consecutive pixels are scarcely changed after the embedding of the secret message by the proposed optimal alteration algorithm. Experimental results have also demonstrated that the proposed scheme is secure against the RS detection attack.

Detection of Double-Compression in JPEG Images for Applications in Steganography

Abstract: This paper presents a method for the detection of double JPEG compression and a maximum-likelihood estimator of the primary quality factor. These methods are essential for construction of accurate targeted and blind steganalysis methods for JPEG images. The proposed methods use support vector machine classifiers with feature vectors formed by histograms of low-frequency discrete cosine transformation coefficients. The performance of the algorithms is compared to selected prior art.

Methods and systems to create big memorizable secrets and their applications in information engineering

Abstract: Main invention is methods and systems to create big and yet memorizable secret, which are later applied into many novel and innovated applications in information engineering. Among the big secret creation methods are (i) self-created signature-like Chinese character, (ii) two-dimensional key (2D key), (iii) multilingual key, (iv) multi-tier geo-image key, (v) multi-factor key using software token, and their hybrid combinations. Multihash key using hash iteration and hash truncation is further used to increase number of created secret for multiple offline and online accounts. Besides, multihash signature using multiple hash values of a message from different hash iteration provides object-designated signature function. The object may be recipient, action, feature, function, meaning, etc., as representation. Also, random space steganography using stego-data with random noise insertion is proposed. The main application of big memorizable secret is MePKC (Memorizable Public-Key Cryptography) using fully memorizable private key. Here, 160- to 512-bit MePKC can be realized.

Chapter 12 – Steganography

Abstract: Publisher Summary This chapter focuses on a specific data-hiding application—steganography. As opposed to digital watermarking, the main property of steganography is statistical undetectability of embedded data. The payload is usually unrelated to the cover Work, which only serves as a decoy. The information-theoretic definition of steganographic security (Cachin's definition) is the most widely used definition in practice. It is usually applied in a simplified form by accepting a model for the cover Work. Secure steganographic schemes must take into account steganalytic methods. One possibility is to replace the embedding operation of LSB flipping (F5) to avoid introducing easily detectable artifacts. Another possibility is to mask the embedding distortion as a naturally occurring phenomenon, such as during image acquisition (stochastic modulation). Alternatively, one can design schemes that preserve some vital statistical characteristics of the cover image (OutGuess) or a model of the cover that is recoverable from the stego Work (model-based steganography). In a typical steganographic scheme, the placement of embedding changes (the selection rule) is shared between the sender and the recipient. However, there are many situations when this information cannot be shared, such as in adaptive steganography, selection rules determined from side information, or in public-key steganography. The problem of nonshared selection rules is equivalent to writing in memory with defective cells and can be efficiently approached using sparse linear codes, known as LT codes.

A Novel Image Steganographic Method Using Tri-way Pixel-Value Differencing

Abstract: To enlarge the capacity of the hidden secret information and to provide an imperceptible stego-image for human vision, a novel steganographic approach using tri-way pixel-value differencing (TPVD) is proposed in this paper. To upgrade the hiding capacity of original PVD method referring to only one direction, three different directional edges are considered and effectively adopted to design the scheme of tri-way pixel-value differencing. In addition, to reduce the quality distortion of stego-image brought from setting larger embedding capacity, an optimal approach of selecting the reference point and adaptive rules are presented. Theoretical estimation and experimental results demonstrate that the proposed scheme can provide superior embedding capacity and give secrecy protection from dual statistical stego-analysis. Besides, the embedded confidential information can be extracted from stego-images without the assistance of original images.

An Information Hiding Scheme Using Sudoku

Abstract: Steganography is the science of secret message delivery using cover media. A digital image is a flexible medium used to carry a secret message because the slight modification of a cover image is hard to distinguish by human eyes. The proposed method is inspired from Zhang and Wang's method and Sudoku solutions. A selected Sudoku solution is used to guide cover pixels' modification in order to imply secret data. Because the number of possible Sudoku solutions is very large, the proposed method is more secure than Mielikainen's method and Zhang and Wang's method. From the experimental results, the visual quality of stego images produced by the proposed method is higher than 44 dB in average, which is slightly less than that of related works; however, the embedding capacity of the proposed method is 1.5 bit per pixel, which is greater than that of the related works.

RGB Intensity Based Variable-Bits Image Steganography

Abstract: In this paper, we present a new algorithm for RGB image based steganography. Our algorithm introduces the concept of storing variable number of bits in each channel (R, G or B) of pixel based on the actual color values of that pixel: lower color component stores higher number of bits. Our algorithm offers very high capacity for cover media compared to other existing algorithms. We present experimental results showing the superiority of our algorithm. We also present comparative results with other similar algorithms in image based steganography.

Information Hiding: A New Approach in Text Steganography

Abstract: Sending encrypted messages frequently will draw the attention of third parties, i.e. crackers and hackers, perhaps causing attempts to break and reveal the original messages. In a digital world, steganography is introduced to hide the existence of the communication by concealing a secret message inside another unsuspicious message. Steganography is often being used together with cryptography and offers an acceptable amount of privacy and security over the communication channel. This paper presents an overview of text steganography and a brief history of steganography along with various existing text-based steganography techniques. Highlighted are some of the problems inherent in text steganography as well as issues with existing solutions. A new approach is proposed in information hiding using inter-word spacing and inter-paragraph spacing as a hybrid method. Our method offers dynamic generated stego-text with six options of maximum capacity according to the length of the secret message. This paper also analyzed the significant drawbacks of each existing method and how our new approach could be recommended as a solution.

Steganography of VoIP streams

Abstract: The paper concerns available steganographic techniques that can be used for creating covert channels for VoIP (Voice over Internet Protocol) streams. Apart from characterizing existing steganographic methods we provide new insights by presenting two new techniques. The first one is network steganography solution which exploits free/unused protocols' fields and is known for IP, UDP or TCP protocols but has never been applied to RTP (Real-Time Transport Protocol) and RTCP (Real-Time Control Protocol) which are characteristic for VoIP. The second method, called LACK (Lost Audio Packets Steganography), provides hybrid storage-timing covert channel by utilizing delayed audio packets. The results of the experiment, that was performed to estimate a total amount of data that can be covertly transferred during typical VoIP conversation phase, regardless of steganalysis, are also included in this paper.

Pixel Indicator High Capacity Technique for RGB Image Based Steganography

Abstract: Image based steganography uses the images as the cover media. LSB is a commonly used technique in this filed. Several scenarios of utilizing least significant bits within images are available. We merge between the ideas from the random pixel manipulation methods and the stego-key ones to propose our work, which uses the least two significant bits of one of the channels to indicate existence of data in the other two channels. This work showed attractive results especially in the capacity of the data-bits to be hidden with relation to the RGB image pixels.

Text Steganography by Changing Words Spelling

Abstract: One of the important issues in security fields is hidden exchange of information There are different methods for this purpose such as cryptography and steganography Steganography is a method of hiding data within a cover media so that other individuals fail to realize their existence In this paper a new method for steganography in English texts is proposed In this method the US and UK spellings of words substituted in order to hide data in an English text For example "color" has different spelling in UK (colour) and US (color) Therefore the data can be hidden in the text by substituting these words

The square root law of steganographic capacity

Abstract: There are a number of recent information theoretic results demonstrating (under certain conditions) a sublinear relationship between the number of cover objects and their total steganographic capacity. In this paper we explain how these results may be adapted to the steganographic capacity of a single cover object, which under the right conditions should be proportional to the square root of the cover size. Then we perform some experiments using three genuine steganography methods in digital images, covering both spatial and DCT domains. Measuring detectability under four different steganalysis methods, for a variety of payload and cover sizes, we observe close accordance with a square root law.

Tamper detection and recovery for medical images using near-lossless information hiding technique.

Abstract: Digital medical images are very easy to be modified for illegal purposes. For example, microcalcification in mammography is an important diagnostic clue, and it can be wiped off intentionally for insurance purposes or added intentionally into a normal mammography. In this paper, we proposed two methods to tamper detection and recovery for a medical image. A 1024 × 1024 x-ray mammogram was chosen to test the ability of tamper detection and recovery. At first, a medical image is divided into several blocks. For each block, an adaptive robust digital watermarking method combined with the modulo operation is used to hide both the authentication message and the recovery information. In the first method, each block is embedded with the authentication message and the recovery information of other blocks. Because the recovered block is too small and excessively compressed, the concept of region of interest (ROI) is introduced into the second method. If there are no tampered blocks, the original image can be obtained with only the stego image. When the ROI, such as microcalcification in mammography, is tampered with, an approximate image will be obtained from other blocks. From the experimental results, the proposed near-lossless method is proven to effectively detect a tampered medical image and recover the original ROI image. In this study, an adaptive robust digital watermarking method combined with the operation of modulo 256 was chosen to achieve information hiding and image authentication. With the proposal method, any random changes on the stego image will be detected in high probability.

Kerckhoffs-Based Embedding Security Classes for WOA Data Hiding

Abstract: It has recently been discovered that using pseudorandom sequences as carriers in spread-spectrum techniques for data-hiding is not at all a sufficient condition for ensuring data-hiding security. Using proper and realistic apriori hypothesis on the messages distribution, it is possible to accurately estimate the secret carriers by casting this estimation problem into a blind source separation problem. After reviewing relevant works on spread-spectrum security for watermarking, we further develop this topic to introduce the concept of security classes which broaden previous notions in watermarking security and fill the gap with steganography security as defined by Cachin. We define four security classes, namely, by order of creasing security: insecurity, key security, subspace security, and stegosecurity. To illustrate these views, we present two new modulations for truly secure watermarking in the watermark-only-attack (WOA) framework. The first one is called natural watermarking and can be made either stegosecure or subspace secure. The second is called circular watermarking and is key secure. We show that circular watermarking has robustness comparable to that of the insecure classical spread spectrum. We shall also propose information leakage measures to highlight the security level of our new spread-spectrum modulations.

A discrete wavelet transform based technique for image data hiding

Abstract: In this paper, a new image data hiding technique based on Discrete Wavelet Transform (DWT) is proposed. The new technique will be used for hiding a secret image S inside a cover image C using two secret keys to obtain a stego-image G. It shows high robustness against many of image processing operations such as lossy compression, blurring, cropping, median filter, sharpen, and addition of noise. The embedded secret image can be extracted with high visual quality. The stego-image is perceptually similar to the original cover image. The proposed technique does not require the original cover image to extract the embedded secret image. The comparative analysis between the proposed technique and the other existing techniques has shown the superiority of the proposed technique.

Steganography of VoIP Streams

Abstract: The paper concerns available steganographic techniques that can be used for creating covert channels for VoIP (Voice over Internet Protocol) streams. Apart from characterizing existing steganographic methods we provide new insights by presenting two new techniques. The first one is network steganography solution which exploits free/unused protocols' fields and is known for IP, UDP or TCP protocols but has never been applied to RTP (Real-Time Transport Protocol) and RTCP (Real-Time Control Protocol) which are characteristic for VoIP. The second method, called LACK (Lost Audio Packets Steganography), provides hybrid storage-timing covert channel by utilizing delayed audio packets. The results of the experiment, that was performed to estimate a total amount of data that can be covertly transferred during typical VoIP conversation phase, regardless of steganalysis, are also included in this paper.

A New Synonym Text Steganography

Abstract: Steganography is a relatively new method for establishing hidden communication which gained attraction in recent years. Steganography is a method of hiding a secret message in a cover media such as image or text. In this paper a new method is proposed for steganography in English text by substituting the words which have different terms in British English and American English.

Multiclass Detector of Current Steganographic Methods for JPEG Format

Abstract: The aim of this paper is to construct a practical forensic steganalysis tool for JPEG images that can properly analyze single- and double-compressed stego images and classify them to selected current steganographic methods Although some of the individual modules of the steganalyzer were previously published by the authors, they were never tested as a complete system The fusion of the modules brings its own challenges and problems whose analysis and solution is one of the goals of this paper By determining the stego-algorithm, this tool provides the first step needed for extracting the secret message Given a JPEG image, the detector assigns it to six popular steganographic algorithms The detection is based on feature extraction and supervised training of two banks of multiclassifiers realized using support vector machines For accurate classification of single-compressed images, a separate multiclassifier is trained for each JPEG quality factor from a certain range Another bank of multiclassifiers is trained for double-compressed images for the same range of primary quality factors The image under investigation is first analyzed using a preclassifier that detects selected cases of double compression and estimates the primary quantization table It then sends the image to the appropriate single- or double-compression multiclassifier The error is estimated from more than 26 million images The steganalyzer is also tested on two previously unseen methods to examine its ability to generalize

A New Steganography Approach for Image Encryption Exchange by Using the Least Significant Bit Insertion

Abstract: Summary A new steganography approach for data hiding is proposed. This approach uses the Least Significant Bits (LSB) insertion to hide data within encrypted image data. The binary representation of the hidden data is used to overwrite the LSB of each byte within the encrypted image randomly. Experimental results show that the correlation and entropy values of the encrypted image before the insertion are similar to the values of correlation and entropy after the insertion. Since the correlation and entropy have not changed, the method offers a good concealment for data in the encrypted image, and reduces the chance of the encrypted image being detected. The hidden data will be used to enable the receiver to reconstruct the same secret transformation table after extracting it and hence the original image can be reproduced by the inverse of the transformation and encryption processes.

Biometric Inspired Digital Image Steganography

Abstract: Steganography is defined as the science of hiding or embedding ";data"; in a transmission medium. Its ultimate objectives, which are undetectability, robustness (i.e., against image processing and other attacks) and capacity of the hidden data (i.e., how much data we can hide in the carrier file), are the main factors that distinguish it from other "; sisters-in science"; techniques, namely watermarking and Cryptography. This paper provides an overview of well known Steganography methods. It identifies current research problems in this area and discusses how our current research approach could solve some of these problems. We propose using human skin tone detection in colour images to form an adaptive context for an edge operator which will provide an excellent secure location for data hiding.

Benchmarking for Steganography

Abstract: With the increasing number of new steganographic algorithms as well as methods for detecting them, the issue of comparing security of steganographic schemes in a fair manner is of the most importance. A fair benchmark for steganography should only be dependent on the model chosen to represent cover and stego objects. In particular, it should be independent of any specific steganalytic technique. We first discuss the implications of this requirement and then investigate the use of two quantities for benchmarking--the KL divergence between the empirical probability distribution of cover and stego images and the recently proposed two-sample statistics called Maximum Mean Discrepancy (MMD). While the KL divergence is preferable for benchmarking because it is the more fundamental quantity, we point out some practical difficulties of computing it from data obtained from a test database of images. The MMD is well understood theoretically and numerically stable even in high-dimensional spaces, which makes it an excellent candidate for benchmarking in steganography. We demonstrate the benchmark based on MMD on specific steganographic algorithms for the JPEG format.

Error Processing of Steganographic Message Signals

Abstract: A form of error processing is used to decode steganographic messages embedded in image and audio signals in the presence of distortion, which tends to introduce errors in steganographic data communication. Content signals with auxiliary embedded data are analyzed to detect embedded message signals. Confidence values are assigned to the message signals and used to ascertain whether a message has been accurately detected. Error processing enables accurate message extraction in the presence of “soft errors” in the embedded message signal. This error processing enables more effective recovery of the steganographic message from content signals that undergo distortion and/or loss transformations after being embedded with steganographic data.