Bit Length Research Articles

An Observation of Non-randomness in NFSR-Based Stream Ciphers with Reduced Initialization Round

The key scheduling phase (KSP) of a stream cipher expands the uniformly chosen key (K) and initialization vector (IV) to a larger uniform looking state. The existence of non-randomness in KSP results in a non-randomness in the final keystream. In this paper, we observe a non-randomness in the KSP of the nonlinear feedback-based stream ciphers Grain-v1, Grain-128AEAD and Fountain-v1 of reduced round R. However, we could not exploit the non-randomness into an attack. It can be claimed that if the KSP generates a pseudorandom state, then the probability of generating a valid state T (i.e., in the range set of KSP function) of a cipher must be $$2^{-\delta }$$ , where $$\delta$$ is the length of padding bits. We show that a new valid state can be constructed by flipping a few bits of a given state of the cipher with a probability higher than $$2^{-\delta }$$ . We show that the non-randomness happens for $$R \le 129$$ , $$R\le 208$$ and $$R \le 193$$ rounds of KSP of Grain-v1, Grain-128AEAD, and Fountain-v1, respectively. Further, in the case of Grain-v1 and Grain-128AEAD, we also found non-randomness in some key, IV bits from the experiment.

A Robust Encrypted Nanocommunication in QCA Circuit

Quantum-dot cellular automata (QCA) is an alternative technology developed to address the fundamental limitations of CMOS technology. This technology is attractive owing to its low power consumption, fast speed, and small dimensions. Cryptography can be a promising application of QCA technology. This paper describes a new way to generate encrypted patterns in QCA that can be helpful in QCA-based secure nano communication. We employed the round robin algorithm for encrypting data in nano communication. The proposed method is useful because it can be employed for the transmission of cipher text obtained using QCA without any limitation on the length of bits in a message. This method can also be used for creating encrypted patterns with high flexibility and scalability.Moreover, in this paper, a novel approximate eight-input majority gate is proposed, making it the first majority gate with even entries. This gate is suitable for designing digital logic circuits, such as priority encoders. However, this design is implemented in a single layer with only 13 cells. The proposed architecture of the majority gate was evaluated and simulated using the QCADesigner tool (version 2.0.3). The results showed 93% accuracy with eight inputs, which result in 256 states. Furthermore, one of these encrypted patterns was used for secure transmission the results approximate eight-input majority gate while considering error states that were recognized in the simulation as encryption keys; thus, we conducted error corrections accordingly.

On the Logical Computational Complexity Analysis of Turbo Decoding Algorithms for the LTE Standards

Evaluating the computational complexity of decoders is a very important aspect in the area of Error Control Coding. However, most evaluations have been performed based on hardware implementations. In this paper, different decoding algorithms for binary Turbo codes which are used in LTE standards are investigated. Based on the different mathematical operations in the diverse equations, the computational complexity is derived in terms of the number of binary logical operations. This work is important since it demonstrates the computational complexity breakdown at the binary logic level as it is not always evident to have access to hardware implementations for research purposes. Also, in contrast to comparing different Mathematical operations, comparing binary logic operations provides a standard pedestal in view to achieve a fair comparative analysis for computational complexity. The usage of the decoding method with fewer number of binary logical operations significantly reduces the computational complexity which in turn leads to a more energy efficient/power saving implementation. Results demonstrate the variation in computational complexities when using different algorithms for Turbo decoding as well as with the incorporation of Sign Difference Ratio (SDR) and Regression-based extrinsic information scaling and stopping mechanisms. When considering the conventional decoding mechanisms and streams of 16 bits in length, Method 3 uses 0.0065% more operations in total as compared to Method 1. Furthermore, Method 2 uses only 0.0035% of the total logical complexity required with Method 1. These computational complexity analysis at the binary logical level can be further used with other error correcting codes adopted in different communication standards.

Compressive sensing chaotic encryption algorithms for OFDM-PON data transmission.

In this paper, we propose chaotic compressive sensing (CS) encryption algorithms for orthogonal frequency division multiplexing passive optical network (OFDM-PON), aiming at compressing the transmitted data and enhancing the security of data transmission. Bitstream transmission using CS directly is restricted due to its inability to satisfy the sparsity in neither time nor frequency domain. While the sparsity of the transmitted data can be constructed when transmitting the multimedia. A sensor can be then used to identify whether the data is multimedia. If it is, the CS technique is used, and the sensor's result is set as side information inserted into the pilot and transmitted to the terminal simultaneously. For encryption processing, a 2-dimensional logistic-sine-coupling map (2D-LSCM) is used to generate pseudo-random numbers to construct the first row of a measurement matrix to encrypt the system. Four transform formats are then applied to generate the sparsity of the transmitted data. Due to the restriction of data transmission in the physical layer, the discrete cosine transform (DCT) is chosen to conduct the CS technique. Four approximation algorithms are also proposed to optimize the performance of compressing the length of bits. We find that 'Round + Set negative to 0' shows the best performance. The combination of this chaotic CS encryption technique with the OFDM-PON systems saves the bandwidth and improves the security.

Исследования и анализ эффективности волоконно-оптических линий связи с использованием квантовой технологии

The analysis of the performance indicators fiber-optic communication lines (FOCL) using quantum technology based on the architectural concept of NGN (Next Generation Network) and future networks FN (Future Networks) for the construction highly efficient optical telecommunication networks supporting a wide range cryptographic resistance. Threats of unauthorized access, denial of service, loss information, cryptographic methods and algorithms for information protection are considered. Complex criteria of FOCL efficiency using such quantum technologies as network performance using WDM (Wavelength Division Multiplexing) technology, information security characteristics when using quantum cryptography protocols, taking into account resistance to various threats, informative characteristics photon sources are selected. A new approach is proposed for the study and assessment of complex indicators complex optical information protection systems and effective control of a set quantum key distribution systems for fiber-optic communication lines. The functioning of the investigated FOCL using quantum technology based on the principles "Point-to-point" network topology, which allows organizing a quantum information and service channel, is considered. On the basis of the proposed approach, the efficiency quantum key distribution, the capabilities quantum cryptography protocols under the influence of photon number splitting attack (PNS-Photon Number Splitting Attack) and the information entropy of the characteristics of sources of optical photon qubit fluxes are investigated. Analytical expressions are obtained for assessing the complex indicators of the information security system when using quantum key distribution (QKD) for FOCL. On the basis of the new approach, a numerical analysis was carried out and a graphical dependence of the information entropy of the packet on the packet length in qubits was constructed for the given transfer characteristics of the FOCL. It was found that an increase in the limited packet length in bits, which meets the requirements reliability and efficiency of the operation FOCL system, leads to an increase in the value information entropy as a fraction of the packet, at a given bit rate of the network.

A Biologically Inspired Algorithm for Low Energy Clustering Problem in Body Area Network

The growing application of body area networks (BANs) in different fields makes the low energy clustering a paramount issue. A clustering optimization algorithm in BANs is a fundamental scheme to guarantee that the essential collected data can be forwarded in a reliable path and improve the lifetime of BANs. Low energy clustering is a technique, which provides a method that shows how to reduce network communication costs in BANs. A careful low energy clustering scheme is one of the most critical means in the research of BANs, which has attracted considerable attention, comprising monitoring capability constraints. However, the classical clustering method leads to high cost when constraints such as large overall energy consumption are undertaken. Hence, a binary immune hybrid artificial bee colony algorithm (BIHABCA), a randomized swarm intelligent scheme applied in BANs, motivated by immune theory and hybrid scheme is introduced. Furthermore, we designed the formulation that considers both distances between two nodes and the length of bits. Finally, we have compared the energy cost optimized by BIHABCA with a shuffled frog leaping algorithm, ant colony optimization, and simulated annealing in the simulation with different quantity of nodes in terms of energy cost. Results show that the energy cost of the network optimized by the proposed BIHABCA method decreased compared to those by the other three methods which mean that the proposed BIHABCA finds the global optima and reduces the energy cost of transmitting and receiving data in BANs.

Exploiting Laguerre transform in image steganography

Steganography, an approach used to conceal information into the digital media, generally works in two domains: spatial and transform. Though spatial domain methods are simpler, but transform domain methods are good at identifying the features which make the end system more secure. In this work, a novel Steganographic scheme based on an integer sequence named Laguerre transform (LT) is proposed. The Cover image is decomposed into non-overlapping m-pixel groups and then each such pixel group is transformed by applying LT. Variable length bits from the secret information are fabricated into the transformed components. A post-embedding adjustment is applied over these components to minimize the distortion. By applying Inverse LT (ILT), the m-pixel groups are re-computed from the resulting adjusted components. Experimental results reveal that disparity between cover and stego-pixels increases as m increases. Proposed scheme offers better stego image and higher payload compared to some state-of-the-art techniques. Code of this method is publicly available here.

Deep Neural Network Media Noise Predictor Turbo-Detection System for 1-D and 2-D High-Density Magnetic Recording

This article presents a concatenated Bahl–Cocke–Jelinek–Raviv (BCJR) detector, low-density parity-check (LDPC) decoder, and deep neural network (DNN) architecture for a turbo-detection system for 1-D and 2-D magnetic recording (1DMR and TDMR). The input readings first are fed to a partial response (PR) equalizer. Two types of the equalizer are investigated: a linear filter equalizer with a 1-D/2-D PR target and a convolutional neural network (CNN) PR equalizer that is proposed in this work. The equalized inputs are passed to the BCJR to generate the log-likelihood-ratio (LLR) outputs. We input the BCJR LLRs to a CNN noise predictor to predict the signal-dependent media noise. Two different CNN interfaces with the channel decoder are evaluated for TDMR. Then, the second pass of the BCJR is provided with the estimated media noise, and it feeds its output to the LDPC decoder. The system exchanges LLRs between BCJR, LDPC, and CNN iteratively to achieve higher areal density. The simulation results are performed on a grain flipping probabilistic (GFP) model with 11.4 Teragrains per square inch (Tg/in2). For the GFP data with 18 nm track pitch (TP) and 11 nm bit length (BL), the proposed method for TDMR achieves 27.78% areal density gain over the 1-D pattern-dependent noise prediction (PDNP). The presented BCJR-LDPC-CNN turbo-detection system obtains 3.877 Terabits per square inch (T/bin2) areal density for 11.4 Tg/in2 GFP model data, which is among the highest areal densities reported to date.

A Unique Way to Generate Password at Random Basis and Sending it Using a New Steganography Technique

Data hiding is a technique for secure transmission of confidential data. Many data hiding techniques exist and steganography is the most important one. This paper presents a new steganography method in spatial domain. We use steganography to send confidential information from sender to receiver. Here, we generate password at random basis in a unique way based on system time and date. Then we send this confidential password using steganography by implementing a totally new embedding and extraction technique based on exact length of bits in binary representation of ASCII values. Here, confidential text information is embedded into cover image generating a stego image and sent to receiver maintaining top level secrecy.

A Unique Way to Generate Password at Random Basis and Sending it Using a New Steganography Technique

Data hiding is a technique for secure transmission of confidential data. Many data hiding techniques exist and steganography is the most important one. This paper presents a new steganography method in spatial domain. We use steganography to send confidential information from sender to receiver. Here, we generate password at random basis in a unique way based on system time and date. Then we send this confidential password using steganography by implementing a totally new embedding and extraction technique based on exact length of bits in binary representation of ASCII values. Here, confidential text information is embedded into cover image generating a stego image and sent to receiver maintaining top level secrecy.

Structure design of weight-on-bit self-adjusting PDC bit based on stress field analysis and experiment evaluation

The complex formations such as soft-hard interbedded and strong abrasive strata in ultra-deep wells make the PDC bit inefficient in rock-breaking, which greatly increases the development cost of oil and gas reservoirs. There are two basic ways to solve the above problems: one way is to relieve the force condition of the bit by changing the working mode and the other is to release the stress of the rock at bottomhole with special tools. A method is proposed in this paper to make full use of the stress-releasing effect to reduce the value of compressive stress of the rock at bottom hole, even turn it into partially tensile stress, and take advantage of the cutting method of ‘Hybrid Bits’ to improve rock-breaking efficiency (RBE). A supporting Weight-on-bit (WOB) Self-adjusting Dual-diameter PDC Bit (WSADB) is invented to realize the above idea. Based on Biot's theory of poroelasticity and considering the fluid-solid coupling effect, numerical calculation of the stress field at well bottom is performed. The results show that the WSADB can improve the RBE by enlarging the volume of the stress unloading area at well bottom; The rock damage function based on the 3D Mohr-Coulomb Criterion is used to analyze the effect of structural parameters of the bit on RBE and the optimal structural parameters are obtained. When the diameter ratio of the pilot bit to the reaming bit is 0.5, the rock to be drilled at the well bottom will be damaged to the greatest extent; When the length of the pilot bit is longer than 0.5 times of the borehole diameter, the longer the length is, the greater the degree of damage to the rock at well bottom will be. To verify the accuracy of the above calculations, a comparative test between the WSADB and conventional PDC bit is performed. The results show that the WSADB has great superiorities in improving the rate of penetration (ROP), lowering the torque on bit (TOB), reducing the mechanical specific energy (MSE) and enhancing the RBE. Making full use of the advantages of higher ROP, smaller TOB and higher mechanical energy utilization of the WSADB is expected to provide a solution to the problem of low RBE of conventional PDC bit in ultra-deep wells.

Soil preparation machine parameters for the cultivation of cucurbitaceous crops

The combined machine allows qualitatively preparing the soil for sowing melon crops with minimum energy consumption. The efficiency of the combined machine depends on the type, location of the tiller relative to the body, and its parameters. The purpose of the study is to justify the type and parameters of the tiller combination machine to prepare the soil for sowing melon crops. In researches methods of classical mechanics are applied. The construction of the combined machine with soil cultivators is given. Based on the theory of soil destruction wedge determined the main parameters of the soil tinker. Experimental research of different types of soil cultivators is carried out. it is established that at the performance of soil cultivator of the combined unit in the form of a three-sided wedge with an inclined stand, the minimum longitudinal distance from a ploughshare of the case to soil cultivator is 52.7 cm, transverse distance from the field cut of the hull to the tiller bit is 15 cm, width and length of the tiller bit is 5 and 14 cm respectively, cutting angle of the bit is 18 degrees, quality crushing of sub-powder soil layers with minimum energy consumption is provided.

The soil preparation machine for seeding potatoes on comb

The aim of the research is to substantiate the main parameters of the machine working elements for preparing the soil for sowing on the ridges and their mutual location. The authors have developed a machine that performs all technological operations to prepare the soil for sowing potatoes on the ridges in one pass in the field. The machine performs surface loosening of the soil, strip deep loosening of the soil, formation of ridges, loosening of the surface layer of the ridge top, compaction, and giving them a trapezoidal shape in one pass. The design of the developed machine for the realization of technology of preparing the soil for potatoes sowing is resulted. The basic principles and methods of classical mechanics, mathematical analysis, and statistics were used in this study. Theoretical studies established the following parameters of the working bodies of the machine: the working width of the bodies 200 mm, length of the blade wing 515-545 mm, angle of slope of the ploughshare left to its base 60, length and height of the guide knife respectively 150 mm and 80 mm, the longitudinal distance between the bodies within 350-400 mm, width and length of the drill bit 80 mm and 115 mm respectively, the working width of the lancet leg 150 mm.

Event-Driven ECG Sensor in Healthcare Devices for Data Transfer Optimization

The long-term monitoring of cardiovascular signs requires a wearable and connected electrocardiogram (ECG) healthcare device. It increases user’s comfort and diagnosis quality of chronic cardiac and/or high-risk patients. This paper covers the enormous data to be transmitted from the ECG device to the physician’s, namely the cardiologist’s, control unit. Existent ECG devices uniformly sample analog signals and convert them to digital samples which are compressed before data transmission. However, event-driven sampling simultaneously compresses and samples. Therefore, this paper quantitatively compares successive approximation register analog-to-digital converter (SAR ADC) with discrete wavelet transform (DWT) compression and level-crossing analog-to-digital converter (LC-ADC). Evaluation metrics are the percent root-mean-square difference ( {text{PRD}} ), bit compression ratio ( {text{BCR}} ) and data length in bits. When a 12-bit reconstruction is operated on the outputs of an 8-bit LC-ADC with 12-bit and 10-kHz reference counter, the {text{BCR}} is equal to 80% for 75% of test ECG signals. That is better than the 71.87% {text{BCR}} of the 12-bit 1-kHz SAR ADC with DWT compression. The modeled LC-ADC guarantees a signal quality in terms of {text{PRD}} comparable to the {text{PRD}} of the SAR ADC with DWT compression. The data length in bits of the LC-ADC is lower than the data length in bits of the SAR ADC with more than 14-bit resolution with DWT compression for 82% of the test ECG signals. However, for lower resolutions, to obtain lower power consumption for radiofrequency transmission, a better alternative remains the SAR ADC with DWT compression.

A differential fault attack on the WG family of stream ciphers

WG-l ($$l=7,8,16,29$$) are the well-known Welch–Gong (WG) stream cipher family with different key length bits. The first version named WG (WG-29) stream cipher was introduced in eSTREAM project as a cipher suitable for hardware implementations. The other variants are proposed for different applications from RFID to fast communications. This paper presents an extensive fault analysis on the WG family. Fault attacks are powerful cryptanalytic tools to analyse cryptosystems, which are not vulnerable to other known cryptographic attacks. The security model used to analyse the WG ciphers applies random faults, which are allowed to be injected by an adversary. The adversary has no control over the fault locations and their values. For each WG-l stream cipher, an adversary needs to observe a specific number of keystream bits before they are able to recover the secret key. To recover the secret key of WG-8, the adversary needs to inject about six random faults and compute the secret key with data and time complexities about $$2^{15.78}$$ bits and $$2^{24}$$, respectively. The adversary can recover the secret key of WG-7, WG-16 and WG-29 ciphers with time complexities $$2^{22}$$, $$2^{42}$$ and $$2^{64}$$, respectively. The attacks have been verified experimentally.

AVBH: Asymmetric Learning to Hash with Variable Bit Encoding

Nearest neighbour search (NNS) is the core of large data retrieval. Learning to hash is an effective way to solve the problems by representing high-dimensional data into a compact binary code. However, existing learning to hash methods needs long bit encoding to ensure the accuracy of query, and long bit encoding brings large cost of storage, which severely restricts the long bit encoding in the application of big data. An asymmetric learning to hash with variable bit encoding algorithm (AVBH) is proposed to solve the problem. The AVBH hash algorithm uses two types of hash mapping functions to encode the dataset and the query set into different length bits. For datasets, the hash code frequencies of datasets after random Fourier feature encoding are statistically analysed. The hash code with high frequency is compressed into a longer coding representation, and the hash code with low frequency is compressed into a shorter coding representation. The query point is quantized to a long bit hash code and compared with the same length cascade concatenated data point. Experiments on public datasets show that the proposed algorithm effectively reduces the cost of storage and improves the accuracy of query.

Anonymous communication scheme based on quantum walk on Cayley graph

Information security is the cornerstone and lifeblood of national security in the information society, and anonymous quantum communication is one of the important ways to protect information security. Using quantum walk randomness to effectively solve sensitive problems such as leakage of identity information. In this paper, an anonymous communication scheme based on quantum walks on the Cayley graph is proposed. First, both parties in the communication hide their identity information, and the sender Alice anonymously selects the receiver Bob through logic or operation. Secondly, the trusted third party and the communicating parties use the BB84 protocol to generate and distribute the security key. Alice encrypts the information sequence according to the security key to obtain the blind information; Bob uses the joint Bell state measurement and security key to sign and the trusted third party verifies the signature information. Third, the trusted third party calculates the position probability distribution function of Bob’s quantum walk via the Fourier transform, converts the position information corresponding to the maximum probability into a confirmation frame and sends it to Alice; Alice uses the quantum compression algorithm by decreasing dimensions to reduce the number of transmitted information bits(the length of the information bit can be reduced by up to 37.5%) and uses the security key to complete the information encryption and then transmit the information to the location indicated by the confirmation frame. Bob uses quantum walks to search the location node to obtain the transmission information and complete the anonymous quantum communication. Finally, the security analysis of the scheme is carried out, and the numerical simulation results of the Cayley graph of 200 nodes are given. At the 10-step walk, the maximal probability of the 6th node is 45.31%. According to the simulation results, the probability that Bob is eavesdropped on the specific location at his 10-step walk during the communication of this scheme is approximately 6 × 10<sup>–7</sup>%, so the receiver can avoid the identity information from the eavesdropping with a high probability, and the quantum network anonymity protocol is not broken.

Data security based on homographic function

In this paper, we adapt a homographic function to encrypt digital images, which takes into account the value of the pixel as well as its position in the image. The homographic function is a function represented as a quotient of two affine functions in a switching field K; it is represented by four different coefficients of zeros, which must verify certain conditions. One take the field K equal Z/257Z switching field (257 is a prime number), (all its non-zero elements are invertible, we take into account the following condition if we have 0 as the pixel value we put 256), 256 is the inverse of 256 in Z/257Z.We will show that this a homophonic substitution, which can represent the confusion part in a modern cryptographic system. We strengthened this proposal by a diffusion method and, we have used the Hénon attractor of is 2-dimensional; each pixel will be permuted to another position of the encrypted image. We managed to build a cryptosystem who passed all the statistic tests, and that has a secret key of 253 bits in length.

A Spectrally Efficient Uplink Transmission Scheme Exploiting Similarity Among Short Bit Blocks

Next-generation cellular systems are anticipated to support 100 times higher data rates (ultra-high rate) compared with the fourth generation (4G) of cellular systems. It is, therefore, necessary to develop novel spectrally efficient uplink/downlink techniques. Multiple techniques have been proposed, including the so-called non-orthogonal multiple access (NOMA) technique. However, the spectral efficiency gains achieved by NOMA over OMA techniques have been shown to be modest. Recently, we proposed a spectrally efficient technique for the downlink channel, which involves exploiting similarities among users’ short bit blocks, where we showed that spectral efficiency gains of up to three times that of OMA schemes can be achieved. However, the technique cannot be extended to the uplink scenario because users are not aware of each other’s bit block. To this end, we propose in this paper a spectrally efficient scheme for the uplink channel, where we exploit the similarity between the short bit blocks of the uplink and downlink sequences corresponding to one user. The downlink bit sequences are those received by a user from the base station (BS). It is assumed that the BS keeps track of the bit sequences transmitted on the downlink channel to different users. The uplink and downlink bit sequences, which are assumed to be uncorrelated, are divided into bit blocks of short lengths, and then, the similarity between those blocks is extracted. Once each user determines its similarity index (i.e., the number of similar bit blocks) between its own bit sequence and its respective downlink bit sequence, this information is communicated with the BS, which will, in turn, select the user with the largest similarity index to transmit during that resource block. The same process repeats every resource block where the user with the maximum similarity index is always selected. We propose a simple overhead exchange algorithm that facilitates the exchange of the information on the similarity indexes between the users and the BS, where we assume that this exchange of information is done through a control channel. The performance of the proposed scheme and the overhead exchange algorithm is investigated analytically and by Monte Carlo simulations. Among the parameters that we incorporate into the analysis are the user density, the length of bit blocks used to check the similarity index, and the channel correlation. We show that spectral efficiency gains of approximately two times that of OMA schemes can be achieved.

A VLIW architecture stream cryptographic processor for information security

As an important branch of information security algorithms, the efficient and flexible implementation of stream ciphers is vital. Existing implementation methods, such as FPGA, GPP and ASIC, provide a good support, but they could not achieve a better tradeoff between high speed processing and high flexibility. ASIC has fast processing speed, but its flexibility is poor, GPP has high flexibility, but the processing speed is slow, FPGA has high flexibility and processing speed, but the resource utilization is very low. This paper studies a stream cryptographic processor which can efficiently and flexibly implement a variety of stream cipher algorithms. By analyzing the structure model, processing characteristics and storage characteristics of stream ciphers, a reconfigurable stream cryptographic processor with special instructions based on VLIW is presented, which has separate/cluster storage structure and is oriented to stream cipher operations. The proposed instruction structure can effectively support stream cipher processing with multiple data bit widths, parallelism among stream cipher processing with different data bit widths, and parallelism among branch control and stream cipher processing with high instruction level parallelism; the designed separate/clustered special bit registers and general register heaps, key register heaps can satisfy cryptographic requirements. So the proposed processor not only flexibly accomplishes the combination of multiple basic stream cipher operations to finish stream cipher algorithms. It has been implemented with 0.18μm CMOS technology, the test results show that the frequency can reach 200MHz, and power consumption is 310mw. Ten kinds of stream ciphers were realized in the processor. The key stream generation throughput of Grain-80, W7, MICKEY, ACHTERBAHN and Shrink algorithm is 100Mbps, 66.67Mbps, 66.67Mbps, 50 Mbps and 800Mbps, respectively. The test result shows that the processor presented can achieve good tradeoff between high performance and flexibility of stream ciphers.