Message Bits Research Articles

Covert digital communication systems based on joint normal distribution

The correlation coefficient of two consecutive Gaussian sequences is modulated by a binary message bit to achieve a secure communication system. The receiver of the proposed random communication system demodulates the received signal by estimating the correlation coefficient of the transmitted two consecutive sequences. Theoretical bit error rate (BER) expressions in frequency-flat/-selective fading channels with/without Doppler shift are derived. Simulation results show that the proposed system can achieve reasonably low BERs in an additive white Gaussian noise channel as well as a Rayleigh fading channel. More importantly, the proposed system shows good performance in resisting eavesdropping, since the transmitted sequence appears to be a Gaussian noise which is almost always inevitable in the process of wireless communications.

Altering split decisions of coding units for message embedding in HEVC

This paper proposes a novel message embedding solution based on modifying the split decisions of HEVC videos. The encoder starts by computing a mapping between the split decisions of a Coding Unit (CU) and its features variables. This results in model weights that can be used to predict the split decisions. Message embedding is then carried out as a function of the predicted and true split decisions per CU. If the message bit to embed is ‘1’ and the predicted and the true split decisions are different then the true split decision is modified to be identical to the predicted flag. Otherwise if the message bit is ‘0’ and the predicted and the true split decisions are identical, then the true split flag is modified to become different than the predicted flag. We apply this embedding concept at two CU coding levels; 32x32 and 16x16. To extract a message, the decoder starts by regenerating the model weights which are then used to predict split decisions and compare them against the true decisions received in the bit stream. Identical decisions indicate a message bit of ‘1’ and non-identical split decisions indicate a message bit of ‘0’. In the experimental results we examine the prediction accuracy, the effect of the proposed solutions on message payload, the number of modified split decisions and the corresponding impact on video quality. Comparison with an existing solution reveals that the proposed solution is superior in terms in message payload whilst resulting in reduced video distortions.

A new transform domain steganography based on modified logistic chaotic map for color images

The art and science of hiding information by embedding messages in various type of digital media is called steganography. This method performs by replacing bits of multimedia files (such as graphics, sounds and texts) with bits of secret message. The information that embeds in the cover media can be plain text, cipher text and even images. Steganography sometimes is used when encryption is not permitted or more commonly, steganography is supplement for encryption. By using steganography, if the encrypted file is deciphered, the encrypted file may still hide information. This paper is proposed a new transform domain steganography method based on integer wavelet transform (IWT) for digital images and also it used a chaotic map. This map is a modified logistic map which it increases the key length and security of proposed method. Experimental results shows that the proposed method has high capability in hiding information in any images which used as a cover media. Visual quality of image after embedding process is desirable due to Peak Signal-to-Noise Ratio (PSNR) measures. Also the NIST, DIEHARD and ENT tests suite show the proposed chaotic map randomness and sensitivity to smallest changes.

An RGB colour image steganography scheme using overlapping block-based pixel-value differencing.

This paper presents a steganographic scheme based on the RGB colour cover image. The secret message bits are embedded into each colour pixel sequentially by the pixel-value differencing (PVD) technique. PVD basically works on two consecutive non-overlapping components; as a result, the straightforward conventional PVD technique is not applicable to embed the secret message bits into a colour pixel, since a colour pixel consists of three colour components, i.e. red, green and blue. Hence, in the proposed scheme, initially the three colour components are represented into two overlapping blocks like the combination of red and green colour components, while another one is the combination of green and blue colour components, respectively. Later, the PVD technique is employed on each block independently to embed the secret data. The two overlapping blocks are readjusted to attain the modified three colour components. The notion of overlapping blocks has improved the embedding capacity of the cover image. The scheme has been tested on a set of colour images and satisfactory results have been achieved in terms of embedding capacity and upholding the acceptable visual quality of the stego-image.

High-Capacity Reversible Data Hiding in Encrypted Images using MSB Prediction

With the development of cloud computing, data privacy has become a major problem. Reversible data hiding in encrypted images (RDHEI) is an effective technique to embed data in the encrypted domain. Indeed, a lot of methods have been proposed, but none allows a large amount of embedding capacity with a perfect reversibility. In this work, we present a new method of reversible data hiding in encrypted images using MSB (most significant bit) prediction. In order to reconstruct the original image without any errors during the decryption phase, we adapt the to-be-inserted message. Some of the pixels' MSB values are used to highlight the prediction errors and the remaining values are replaced by bits of the secret message. Results show that it is still possible to embed a large message (payload close to 1 bpp).

Dual image based reversible data hiding scheme using (7,4) hamming code

In this paper, we propose a new dual-image based reversible data hiding scheme through (7,4) Hamming code (RDHHC) using shared secret key. A block of seven pixels are collected from cover image and copied into two arrays then it is adjusted redundant Least Significant Bits (LSBs) using odd parity such that any error creation is encountered at the sender end and recovered at the receiver end. Before data embedding, we first complement the bit at shared secret position. After that, secret message bit is embedded by error creation caused by tamper in any suitable position except secret position and that error is detected as well as corrected at the receiver end using Hamming error correcting code. One shared secret position κ and one shared secret key ξ help to perform data embedding, data extraction and recovery of the original image. The secret data and original cover image are successfully recovered at the receiver end from dual stego image. Finally, we compare our scheme with other state-of-the-art methods and obtain reasonably better performance in terms of PSNR.

Simplifying FPGA Implementations of BLAKE Hash Algorithm with Block Memory Resources

Malfunctions of contemporary IT systems caused by security violations are so common and frequent that in dependability analysis now they are treated in the same way as the traditional reliability theory considered “classic” failures. For this reason to improve overall system reliability today it is necessary to apply appropriate cryptographic methods. In this paper we are dealing with one class of such methods which are based on so called hash functions, considering one specific method – the BLAKE algorithm. BLAKE was developed as a candidate for the SHA-3 contest where it successfully qualified to the final round and although it eventually lost to KECCAK it is still considered as a suitable solution with good cryptographic strength and sound performance especially in software realizations. In this paper we discuss specific modification of its hardware implementations which use built-in block RAM modules available in contemporary Field Programmable Gate Arrays. The purpose of the modification is to eliminate involved distribution of message bits among the cipher rounds in order to reduce occupation of in-array resources and also to improve performance metrics. The idea is tested on 4 different architectures: the standard iterative one and three high-speed loop-unrolled organizations with 2, 4 and 5 rounds instantiated in hardware. The results found after their implementation in a popular Spartan-3 device form Xilinx are compared to parameters of analogous architectures implemented without memory so that the savings in array utilization can be compared against additional cost incurred by the RAM modules.

Secure Index and Data Symbol Modulation for OFDM-IM

In this paper, we propose a secure index and data symbol modulation scheme for orthogonal frequency division multiplexing with index modulation (OFDM-IM) systems. By exploiting the notion of the channel reciprocity in time division duplexing mode over wireless channels for shared channel state information as a secret key, we investigate randomized mapping rules for index modulation as well as data symbol modulation. Due to the randomized mapping rules for index and data symbol modulation in OFDM-IM, an eavesdropper is not able to correctly decide message bits even though active subcarriers and their symbols are correctly estimated. In particular, we exploit a characteristic of OFDM-IM which uses a fraction of subcarriers for transmissions to enhance security of data symbol modulation. In addition, to design a set of mapping rules for data symbol modulation, we investigate both a random-selection-based set and a bit-mismatch-based set. Through the analysis and simulation results, we demonstrate that the proposed scheme based on the randomized mapping rules for index modulation and data symbol modulation has a better performance than an existing scheme (modified for OFDM-IM) in terms of bit error rate (BER) and successful attack probability. In particular, we can show that the BER at an eavesdropper is much higher if the bit-mismatch-based set of mapping rules is used.

A Novel Data Hiding Algorithm for High Dynamic Range Images

In this paper, we propose a novel data hiding algorithm for high dynamic range (HDR) images encoded by the OpenEXR file format. The proposed algorithm exploits each of three 10-bit mantissa fields as an embedding unit in order to conceal k bits of a secret message using an optimal base which produces the least pixel variation. An aggressive bit encoding and decomposition scheme is recommended, which offers a high probability to convey ( k + 1) bits without increasing the pixel variation caused by message concealment. In addition, we present a bit inversion embedding strategy to further increase the capacities when the probability of appearance of secret bit “1” is greater than 0.5. Furthermore, we introduce an adaptive data hiding approach for concealing more secret messages in pixels with low luminance, exploiting the features of the human visual system to achieve luminance-aware adaptive data hiding. The stego HDR images produced by our algorithm coincide with the HDR image file format, causing no suspicion from malicious eavesdroppers. The generated stego HDR images and their tone-mapped low dynamic range (LDR) images reveal no perceptual differences when subjected to quantitative testing by visual difference predictor. Our algorithm can resist steganalytic attacks from the HDR and LDR RS and SPAM steganalyzers. We present the first data hiding algorithm for OpenEXR HDR images offering a high embedding rate and producing high visual quality of the stego images. Our algorithm outperforms the current state-of-the-art works.

Improved dual-image reversible data hiding method using the selection strategy of shiftable pixels' coordinates with minimum distortion

Compared to conventional reversible data hiding (RDH) methods, the dual-image RDH technique is an effective way to achieve greater embedding rate and better quality of the stego images. Motivated by the center folding-based, dual-image RDH method proposed by Lu et al. (SIGNAL PROCESSING, 115 (2015) 195–213), we propose an improved dual-image RDH method by using the selection strategy of shiftable pixels' coordinates with minimum distortion. Although the stego dual-pixel in the center folding-based method is shifted with minimum distortion, there is another shiftable pixel-coordinate that can be used without creating any extra distortion. Based on this observation, the embedding rate can be improved without any deterioration of visual quality by embedding an extra message bit into each newfound alternative pixel-coordinate. In addition, the range of parameter k, which controls the embedding rate, in our method is extended to greater than or equal to 1, therefore, a higher visual quality can be achieved when k is set at 1. The experimental results showed that the embedding rate of our method is greater than that of the center folding-based method for the same stego image quality, and our method outperforms other methods, whether in term of average PSNR or embedding rate.

Usefulness of multiqubit W-type states in quantum information processing

We analyze the efficacy of multiqubit W-type states as resources for quantum information. For this, we identify and generalize four-qubit W-type states. Our results show that the states can be used as resources for deterministic quantum information processing. The utility of results, however, is limited by the availability of experimental setups to perform and distinguish multiqubit measurements. We, therefore, emphasize on another protocol where two users want to establish an optimal bipartite entanglement using the partially entangled W-type states. We found that for such practical purposes, four-qubit W states can be a better resource in comparison to three-qubit W-type states. For dense coding protocol, our states can be used deterministically to send two bits of classical message by locally manipulating a single qubit.

Data hiding using pseudo magic squares for embedding high payload in digital images

In this paper, a novel information hiding scheme based on pseudo magic squares is proposed. The pseudo magic square pattern is generated using the Knight's move algorithm, whereas diamond encoding (DE) and adaptive pixel pair matching (APPM) embedding schemes adapts rhombic shaped and non-uniform pattern respectively. The momentous feature of the proposed embedding scheme is its ability to generate several pseudo magic squares for a given embedding parameter. On contrary, DE and APPM map one fixed pattern to an embedding parameter. Thus, the proposed system can achieve higher payloads by concealing data using a pattern chosen from a variety of compact neighborhood sets. Depending on the size of the message bits, the order of the pseudo magic square is determined and one pattern among the set of the possible pseudo magic squares can be utilized during the embedding phase. The secret digits are embedded in the cover image based on a randomized sequence. The performance analysis in the experimental results reveal that the proposed algorithm not only provides increased payload with less distortion but also increases the security of the embedding processing by allowing the application to employ one among the several square patterns for every secure communication.

Enhancing embedding capacity and stego image quality by employing multi predictors

Prediction error based reversible schemes, which are of a category of single layer data embedment process, conceal message bits mostly into two distinct embeddable errors, e.g. 0 and −1. In the single layer data embedment schemes, the embeddable errors conceive message bit of ‘0’ and ‘1’ through shifting their values by zero and one unit respectively, while the non-embeddable errors must change their values by one just to assist a process of performing reversibility. Hence, the resulting distortions in the stego image overwhelmingly increase along with the rises in the quantity of non-embeddable errors. Increasing the quantity of embeddable errors, thus, enhances both the embedding space and the stego image quality. The authors in this paper enhance the process of increasing the number of embeddable errors −1 and 0 through employing multi predictors, say n predictors, rather than a single one. The prediction errors of these n predictors are measured first. These n prediction errors, relating to each cover pixel, are further employed into m new linear relations to generate m additional hybrid errors. Each optimal prediction error is then extracted from these n + m errors in a manner so that these can be tracked back by the decoder during the de-embedment of the data bits. Simulation results confirm that the proposed scheme provides almost 10%–9233% higher embedding capacity depending on the texture contents of the cover image, while the image quality is improved compared with the competing ones.

A Survey on Reversible Image Data Hiding with Quality Enhancement

In this paper, a completely unique reversible data hiding (RDH) algorithmic rule is projected for digital images. rather than attempting to keep the PSNR value high, the projected algorithmic rule enhances the contrast of a host image to boost its visual quality. the best 2 bins within the histogram are selected for information embedding in classify that histogram equalisation determination be execute by repeating the method. The side info is embedded in conjunction with the message bits into the host image so the initial image is totally retrievable. The projected algorithmic rule was implemented on 2 sets of images to demonstrate its efficiency. To our greatest knowledge, it's the primary algorithmic rule that achieves image contrast enhancement byRDH. moreover, the analysis results show that the visual quality is preserved once a considerable amount of message bits have been embedded into the contrast-enhanced images, even higher than 3 specificMATLAB functions used for image contrast enhancement.

Reversible Data Hiding in JPEG Images

Among various digital image formats used in daily life, the Joint Photographic Experts Group (JPEG) is the most popular. Therefore, reversible data hiding (RDH) in JPEG images is important and useful for many applications such as archive management and image authentication. However, RDH in JPEG images is considerably more difficult than that in uncompressed images because there is less information redundancy in JPEG images than that in uncompressed images, and any modification in the compressed domain may introduce more distortion in the host image. Furthermore, along with the embedding capacity and fidelity (visual quality), which have to be considered for uncompressed images, the storage size of the marked JPEG file should be considered. In this paper, based on the philosophy behind the JPEG encoder and the statistical properties of discrete cosine transform (DCT) coefficients, we present some basic insights into how to select quantized DCT coefficients for RDH. Then, a new histogram shifting-based RDH scheme for JPEG images is proposed, in which the zero coefficients remain unchanged and only coefficients with values 1 and −1 are expanded to carry message bits. Moreover, a block selection strategy based on the number of zero coefficients in each $8\,\times \,8$ block is proposed, which can be utilized to adaptively choose DCT coefficients for data hiding. Experimental results demonstrate that by using the proposed method we can easily realize high embedding capacity and good visual quality. The storage size of the host JPEG file can also be well preserved.

Exploiting Content Delivery Networks for covert channel communications

Content Delivery Networks (CDNs) became an important infrastructure in today’s Internet architecture. More and more content providers use CDNs to improve their service quality and reliability. However, providing better quality of service (QoS) by using CDNs could also be abused by attackers to commit network crimes. In this paper, we show that CDNs can be used as a covert communication channel to circumvent network censorships. Specifically, we propose the CDN covert channel attack, where accessing contents through different CDN nodes can form a unique pattern, which can be used in encoding secret messages. We implemented a proof-of-concept covert channel based on our proposed attack on CloudFront, a commercial CDN service provided by Amazon Web Service. We showed that our constructed covert channel can transmit messages with various lengths with an average transmission efficiency as 2.29 bits per request (i.e., each penetration request transmits 2.29 bits of secret message on average). After presenting the CDN covert channel attack, we also discuss possible countermeasures.

Cryptanalysis and improvement of quantum broadcast communication and authentication protocol with a quantum one-time pad**Project supported by the National Natural Science Foundation of China (Grant Nos. 61502101 and 61170321), the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20140651), the Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20110092110024), and the Project Funded by PAPD

The security of quantum broadcast communication (QBC) and authentication protocol based on Greenberger–Horne–Zeilinger (GHZ) state and quantum one-time pad is analyzed. It is shown that there are some security issues in this protocol. Firstly, an external eavesdropper can take the intercept–measure–resend attack strategy to eavesdrop on 0.369 bit of every bit of the identity string of each receiver without being detected. Meanwhile, 0.524 bit of every bit of the secret message can be eavesdropped on without being detected. Secondly, an inner receiver can take the intercept–measure–resend attack strategy to eavesdrop on half of the identity string of the other’s definitely without being checked. In addition, an alternative attack called the CNOT-operation attack is discussed. As for the multi-party QBC protocol, the attack efficiency increases with the increase of the number of users. Finally, the QBC protocol is improved to a secure one.

Cryptanalysis of Controlled Quantum Secure Direct Communication and Authentication Protocol Based on Five-Particle Cluster State and Quantum One-Time Pad

A new attack strategy, the so-called intercept-selectively-measure-resend attack is put forward. It shows that there are some security issues in the controlled quantum secure direct communication (CQSDC) and authentication protocol based on five-particle cluster states and quantum one-time pad. Firstly, an eavesdropper (Eve) can use this attack to eavesdrop on 0.656 bit of every bit of the identity string of the receiver and 1.406 bits of every couple of the corresponding bits of the secret message without being detected. Also, she can eavesdrop on 0.311 bit of every bit of the identity string of the controller. Secondly, the receiver can also take this attack to obtain 1.311 bits of every couple of the corresponding bits of the secret message without the permission of the controller, which is not allowed in the CQSDC protocols. In fact, there is another security issue in this protocol, that is, one half of the information about the secret is leaked out unconsciously. In addition, an alternative attack strategy which is called as the selective-CNOT-operation attack strategy to attack this protocol is discussed.

A Technique of Image Steganography using Parity Checker and LSBraille

Today, internet made it easier to send the data more accurately and faster to the destination with the increasing unauthorized access of confidential data. So that, the issue nowadays reduces detection of information during transmission. To hide the secret information during transmission, there are two methods cryptography and steganography. Cryptography is a method of storing and transmitting data in a particular form so that only those for whom it is intended can read and process it. Steganography is a Greek origin word which means “hidden writing”. In this paper, a new image steganography method is proposed. The proposed method hides the secret message inside the cover image by representing the secret message characters using Braille method of reading and writing for blind people. Which all pixels of the cover image can be used and message bit is stored in LSB of one of the three color components Blue (B) only; based on the parity of three LSBs of R, G, and B components of 24-bit color image. From the experimental results it’s founded that the proposed method can hide a lot of data in single RGB image which a few pixels of image can be changed so that method can achieve higher value of (PSNR) and Maximum Hiding Capacity (MHC).

New Approaches to Encrypt and Decrypt Data in Image using Cryptography and Steganography Algorithm

Nowadays, network has important roles for transferring data accurately and fast from source to a destination. The data is not secure enough to transfer highly confidential. The security of information has become one of the principle challenges of resource sharing with data communication over computer network. Cryptography and Steganography are two methods for protecting data from intruders while transferring over an open channel network. Cryptography is a method to encrypt data and steganography is the art and science of hiding secret message in a cover image. In this paper a Hash Least Significant Bit (H-LSB) with Affine cipher algorithm has been proposed for providing more security to data in a network environment. First we encrypt the data with the new cryptography algorithm and then embed in the image. Eight bits of the secret message are divided into 3, 3, 2 and embedding into the RGB pixels values of the cover image respectively. A hash function is used to select the particular position of insertion in LSB bits. This system allows a message sender to select keys to encrypt the secret message before embedding into the image and a receiver is used the keys to decrypt the message. Receiver can be decrypted the encrypt message with incorrect the keys but to a different form from the original message. This system has the ability to provide better security while transferring the secret message from one end to the other end in network environment.