Significant Bit Research Articles

Engineering structured magnetic bits for magnonic holographic memory

Magnonic holographic memory is a type of memory that uses spin waves for magnetic bit read-in and read-out. Its operation is based on the interaction between magnets and propagating spin waves where the phase and the amplitude of the spin wave are sensitive to the magnetic field produced by the magnet. Memory states 0 and 1 are associated with the presence/absence of the magnet in a specific location. In this work, we present experimental data showing the feasibility of magnetic bit location using spin waves. The testbed consists of four micro-antennas covered by Y3Fe2(FeO4)3 yttrium iron garnet (YIG) film. A constant in-plane bias magnetic field is provided by NdFeB permanent magnet. The magnetic bit is made of strips of magnetic steel to maximize interaction with propagating spin waves. In the first set of experiments, the position of the bit was concluded by the change produced in the transmittance between two antennas. The minima appear at different frequencies and show different depths for different positions of the bit. In the second set of experiments, two input spin waves were generated, where the phase difference between the waves is controlled by the phase shifter. The minima in the transmitted spectra appear at different phases for different positions of magnetic bit. The utilization of the structured bit enhances its interaction with propagating spin waves and improves recognition fidelity compared to a regular-shaped bit. The recognition accuracy is further improved by exploiting spin wave interference. The depth of the transmission minima corresponding to different magnet positions may exceed 30 dB. All experiments are accomplished at room temperature. Overall, the presented data demonstrate the practical feasibility of using spin waves for magnetic bit red-out. The practical challenges are also discussed.

A Compact Reconfigurable Resonator-Based Direct Current Sensing System

A compact and reconfigurable current readout system is presented that is based on microelectromechanical system (MEMS) resonators. The proposed system generates analog and digital outputs by electrothermally tuning the microbeam resonant frequency according to variations in the input current signal. A single resonator is utilized to generate the analog output, while a resonator array operating at different frequencies is utilized to generate a digital one-hot output. Experiments showed that the frequency shift is linearly proportional to the square of the current. The single resonator has a detection limit of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.16 ~\mu \text{A}$ </tex-math></inline-formula> , and the resonator array offers good static linearity with a maximum differential/integral non-linearity of 0.55/0.23 least significant bits. The single resonator is suitable for applications requiring high-resolution measurements. The proposed resonator sensing system has a small footprint, is compatible with large-scale integration, and provides considerable flexibility for reconfiguration.

From Chaos to Pseudorandomness: A Case Study on the 2-D Coupled Map Lattice.

Applying the chaos theory for secure digital communications is promising and it is well acknowledged that in such applications the underlying chaotic systems should be carefully chosen. However, the requirements imposed on the chaotic systems are usually heuristic, without theoretic guarantee for the resultant communication scheme. Among all the primitives for secure communications, it is well accepted that (pseudo) random numbers are most essential. Taking the well-studied 2-D coupled map lattice (2D CML) as an example, this article performs a theoretical study toward pseudorandom number generation with the 2D CML. In so doing, an analytical expression of the Lyapunov exponent (LE) spectrum of the 2D CML is first derived. Using the LEs, one can configure system parameters to ensure the 2D CML only exhibits complex dynamic behavior, and then collect pseudorandom numbers from the system orbits. Moreover, based on the observation that least significant bit distributes more evenly in the (pseudo) random distribution, an extraction algorithm E is developed with the property that when applied to the orbits of the 2D CML, it can squeeze uniform bits. In implementation, if fixed-point arithmetic is used in binary format with a precision of z bits after the radix point, E can ensure that the deviation of the squeezed bits is bounded by 2-z . Further simulation results demonstrate that the new method not only guides the 2D CML model to exhibit complex dynamic behavior but also generates uniformly distributed independent bits with good efficiency. In particular, the squeezed pseudorandom bits can pass both NIST 800-22 and TestU01 test suites in various settings. This study thereby provides a theoretical basis for effectively applying the 2D CML to secure communications.

Generating Robust DNN With Resistance to Bit-Flip Based Adversarial Weight Attack

Rowhammer Attack, a new DRAM-based attack, was developed exploiting weak cells to alter their content. Such attacks can be launched at the user level without requiring access permission to the victim memory cells. Leveraging such attacks, a new bit-flip-based adversarial weights attack (BFA) was developed targeting deep neural network models. When BFA attackers acquire a DNN model, they manipulate the existing DNN adversarial attack into locating vulnerable bits in the target DNN model. By flipping a subset of them using Rowhammer, they can crash that model within 30 trails. In this paper, we propose a lightweight and easy-to-deploy defense mechanism in the bit-level, Randomized Rotated and Nonlinear Encoding (RREC), which generates both robustness and fault-tolerant against BFA. Since flipping the most significant bit (MSB) in quantized data is too dangerous, we introduce randomized Rotation to obfuscate the bit order of model data and efficiently hide truly vulnerable bits with less vulnerable ones. Further, RREC reduces the average bit-flipped distance by more than 3x from the nonlinear encoding. It decreases the bit-flip distance among the majority of bits (including those vulnerable bits). Theoretically, RREC minimized the impact of a single bit BFA to 1/24 compared with baseline. Experimentally, RREC tolerates more than 17x flipped bits versus baseline model and 4.8x and 5.7x more bits compared with the existing BFA defenses (4B QAT and WR) with 0.01x to 0.08x of runtime latency. Moreover, we evaluate RREC against a newly emerged attack, Targeted-BFA, and it improves the defense rate from <inline-formula><tex-math notation="LaTeX">$5\%$</tex-math></inline-formula> to <inline-formula><tex-math notation="LaTeX">$95\%$</tex-math></inline-formula> .

A 128-channel time-to-digital converter based on the 24-phase shift-clock sampling method for RPC

The Resistive Plate Chamber (RPC) are widely used in high energy physics (HEP) experiments. In recent years, new designs and application scenarios of RPCs abound, and an advanced time-to-digital converter (TDC) system is in demand. The TDC implemented in the field-programmable gate array (FPGA) is widely used in HEP experiments with changeable conditions as a flexible time measurement method. This article presents a multi-phase shift-clock sampling FPGA-based TDC with 128 channels. The TDC module is implemented in a Xilinx Kintex-7 FPGA. The sampling clock period (2.22 ns) is subdivided into 24 phases to achieve finer time resolution. The TDC performance measurements show that the root-mean-square (RMS) time resolution of the TDC module in the time interval measurement is 45.3 ∼ 57.7 ps, and the integral nonlinearity (INL) is smaller than 0.2368 least significant bit (LSB). In addition, some target designs are made to adapt to the application scenarios. This article also shows measurement results acquired from an RPC by this TDC. This TDC was used to measure the RPC efficiency plateau and the TOT of the RPC readout signal.

Blind Identification of Polar Codes Based on Estimation and Derivation Approaches

The blind identification of polar codes is to identify code parameters such as the code length, the number and positions of information bits in a polar code in non-cooperative communications. In this letter, we propose two low-complexity algorithms to identify code length and information bits of polar codes, respectively, by taking the union of both the estimated code parameters and the derived code parameters from the allowable shortest code without the candidate code sets. Simulations show that our proposed scheme is robust to the error and significantly improves the identification performance as compared to the existing purely code parameter estimation approaches.

PENERAPAN CAESAR CHIPER DAN LEAST SIGNIFICANT BIT UNTUK MENGAMANKAN DATA REKAM MEDIS

Technological developments in data security systems in maintaining information security have grown rapidly. Medical record is a document that contains personal data and medical history and medical treatment history of a patient at a hospital. Medical records are sensitive and confidential so that not just anyone can read the information in the patient's medical record. This study aims to secure patient medical record information by encrypting it with caesar cipher cryptography, the name of the patient's disease, then from the results of the encryption, the process of inserting the encrypted information into a digital image uses the least significant bit (LSB) steganography, namely replacing 1 digit behind the binary number in every 1 bit. The results of the study show that the application created is capable of encrypting and encoding patient medical record data information and embedding this information into digital images.

Image Watermarking Using Least Significant Bit and Canny Edge Detection.

With the advancement in information technology, digital data stealing and duplication have become easier. Over a trillion bytes of data are generated and shared on social media through the internet in a single day, and the authenticity of digital data is currently a major problem. Cryptography and image watermarking are domains that provide multiple security services, such as authenticity, integrity, and privacy. In this paper, a digital image watermarking technique is proposed that employs the least significant bit (LSB) and canny edge detection method. The proposed method provides better security services and it is computationally less expensive, which is the demand of today's world. The major contribution of this method is to find suitable places for watermarking embedding and provides additional watermark security by scrambling the watermark image. A digital image is divided into non-overlapping blocks, and the gradient is calculated for each block. Then convolution masks are applied to find the gradient direction and magnitude, and non-maximum suppression is applied. Finally, LSB is used to embed the watermark in the hysteresis step. Furthermore, additional security is provided by scrambling the watermark signal using our chaotic substitution box. The proposed technique is more secure because of LSB's high payload and watermark embedding feature after a canny edge detection filter. The canny edge gradient direction and magnitude find how many bits will be embedded. To test the performance of the proposed technique, several image processing, and geometrical attacks are performed. The proposed method shows high robustness to image processing and geometrical attacks.

Security enhancement of quantum noise stream cipher system based on optical temporal scrambling

In order to enhance security of QNSC signal, an optical temporal scrambling scenario which can avoid leaking synchronous clock parameters in QNSC system is proposed and experimentally demonstrated. In the proposed scenario, it utilized a cascaded FPCs to disturb time signature of 12.5 Gbps QNSC with 1024(210) intensity levels. The results indicate that, optical temporal scrambler cascaded 36 FPCs can spread the QNSC signal, resulting in the neighboring 12.5 bits of QNSC signal may be overlapped, which makes the signal look like noise both in intensity level and in time domain. Then, the descrambling process can be implemented by a matched filter corresponding to the optical temporal descrambling. Furthermore, by analyzing the scrambled QNSC signals, the power penalty caused by transmission for 50.8 km is about 3.22 dB. As for its actual effect, it greatly enhanced the security of the QNSC signal due to the concealment of time features.

A SYSTEMATIZED APPROACH TO DATA HIDING USING IMPROVED LSB

Aim: This paper mainly focused on introducing a new framework for image and text hiding using a simple Least Significant Bit (LSB) substitution method.&nbsp; Results: Six 24-bit images are used as reference images. XOR operation is used in the stego key to generate new bit planes of the stego images. An RGB color image is used as a secret cover image. The proposed method dramatically increases the embedding capacity without significantly decreasing the Peak Signal-to-Noise Ratio (PSNR) value.&nbsp; Conclusion: This method increased the compression ratio, embedding ratio, PSNR and Space 24%, 53%, 36% and 47%, respectively. The result shows that the newly developed method improved the value of accuracy by 30% and sensitivity by 16% for the hidden images. &nbsp;Keywords: LSB, PSNR, FNR (False Negative Rate), Sensitivity, MSE (Mean Square Error), Specificity HIGHLIGHTS: The newly developed method with simple Least Significant Bit (LSB) improved the accuracy value by 30%, and sensitivity by 16% for the hidden image. The improved LSB method increased security and preserved the quality of hidden images.

Reversible demosaiced image authentication scheme with recoverability using clustering and matching techniques

In this paper, we propose a reversible and recoverable authentication technique for demosaiced images using the k-means clustering algorithm and side match technique. Prior methods generate the recovery codes directly using the most significant bits of sampled components or their compressed codes, which requires excessive bits to record them. This not only damages the image to a large extent, but also limits the quality of the recovered image. In this paper, the sampled components are clustered and their cluster indices are used as the recovery codes. A tampered block can mostly be recovered by other untampered ones with the same cluster index. For an unrecoverable block, the cluster indices of its neighboring untampered blocks are employed to predict the block, and the recovery is performed by using the side match technique. Since unrecoverable blocks are sparsely scattered in the tampered areas, the recovered blocks around them are mostly available, and therefore an accurate prediction can be made. The experimental results show that the average quality of marked and recovered images of our method increases by around 3.36 dB and 2.96 dB, respectively, compared to previous methods.

Predicting positions of flipped bits in robust image hashes

Both robust and cryptographic hash methods have advantages and disadvantages. It would be ideal if robustness and cryptographic confidentiality could be combined. The problem here is that the concept of similarity of robust hashes cannot be applied to cryptographic hashes. Therefore, methods must be developed to reliably intercept the degrees of freedom of robust hashes before they are included in a cryptographic hash, but without losing their robustness. To achieve this, we need to predict the bits of a hash that are most likely to be modified, for example after a JPEG compression. We show that machine learning can be used to make a much more reliable prediction than the approaches previously discussed in the literature.

A High-Capacity Coverless Information Hiding Based on the Lowest and Highest Image Fragments

Coverless data hiding is resistant to steganalytical tool attacks because a stego image is not altered. On the other hand, one of its flaws is its limited hiding capacity. Recently, a coverless data-hiding method, known as the coverless information-hiding method based on the most significant bit of the cover image (CIHMSB), has been developed. This uses the most significant bit value in the cover image by calculating the average intensity value on the fragment and mapping it with a predefined sequence. As a result, CIHMBS is resistant to attack threats such as additive Gaussian white noise (AGWN), salt-and-pepper noise attacks, low-pass filtering attacks, and Joint Photographic Experts Group (JPEG) compression attacks. However, it only has a limited hiding capacity. This paper proposes a coverless information-hiding method based on the lowest and highest values of the fragment (CIHLHF) of the cover image. According to the experimental results, the hiding capacity of CIHLHF is twice that of CIHMSB.

Quantum grayscale image encryption and secret sharing schemes based on Rubik’s Cube

In order to encrypt and safely share images using quantum computer, a quantum grayscale image encryption scheme and a quantum grayscale image secret sharing scheme are proposed in this paper. According to Rubik’s Cube rotation method, this paper initially puts forward the quantum Rubik’s Cube rotation scrambling scheme (QRRSS) to permute the pixel position. Then, based on QRRSS, quantum XOR operation and quantum SWAP operation, we design the quantum image encryption scheme. Finally, we propose a quantum image secret sharing scheme. In the secret sharing scheme, one secret image and six cover images are encrypted. Quantum least significant bit (LSB) method is used to stego the secret image into four randomly chosen cover images in order to generate four shadow images. The shared secret image can be recovered if all the shadow images can be collected from all participants. We then design the whole quantum circuits of two proposed schemes and finish simulation experiments. The simulation results indicate that our encryption scheme and secret sharing scheme have good effect. It is worth noting that the computational complexity of our two proposed quantum algorithms is exponentially decreased than the classical counterparts.

A 10-bit CS-DAC using Fully Random Rotation based DEM and code independent output impedance compensation

This article presents a low power high dynamic performance 10-bit Current Steering Digital-to-Analog Converter (CS-DAC), which utilizes a novel Fully Random Rotation-based Dynamic Element Matching (FRR-DEM) technique and Code Independent Impedance Compensation (CIIC) method. The mismatch induced non-linearities are suppressed by proposed FRR-DEM , while at high frequency, the distortion due to code dependent load variation is compensated by CIIC technique to achieve the high Spurious Free Dynamic Range (SFDR). The FRR-DEM efficiently performs the rotation and binary to thermometer conversion of input Upper Least Significant Bits(ULSB) and Most Significant Bits (MSB) in a random fashion. In view of digital area complexity, this randomizer utilizes minimum number of transistors compared to the conventional state-of-the-art DEM DACs without compromising the dynamic performances and also it adds an additional level to averaging out the amplitude mismatch errors. The complete CS-DAC is designed using 180 nm CMOS process and the post-layout mismatch based simulation results are presented. This DAC achieves SFDR of more than 66 dB at 500 MS/s sampling frequency over entire Nyquist band with a 17 dB improvement from the conventional DAC. The proposed DAC acquires an active area of 0.31 mm2 and the post-layout simulated power consumption is 23 mW from a single 1.8 V supply.

Combination RC4 Algorithm and Base64 Encryption on The Least Significant Bit Method

Steganography is an art form of hiding data or information on a medium. Steganography was created as a way to secure data by hiding it in other media so that it is "invisible". In steganography, secret data is hidden in a carrier such as sound, image or video. Securing messages using steganography is still vulnerable to third parties because the message inserted is still the original message, so that when it is successfully deleted from the message carrier it can be immediately identified. Given these problems, the steganography method needs to be combined with other methods to strengthen the level of data security, in this case a combination of steganography and cryptography will be carried out so that the embedded message will be different from the original message. Even if the data is deleted from the user, the message cannot be known immediately. In this trial, the RC4 cryptographic method which has a symmetric key and also Base64 will be implemented in the PHP and Android programming languages using the Least Significant Bit (LSB) steganography method which will create encrypted secret messages embedded in JPG format, JPEG image media formats on each the last bit of a pixel so that the eye does not see the difference between the inserted and non-inserted images with the original image variable/result of 131.91KB after the Encryption process the amount of data is 31.92KB with very small differences so that data security is maintained without being visible to the naked eye

AN EFFICIENT ALGORITHMIC SOLUTION FOR HIGH PAYLOAD GOOD IMPERCEPTIBILITY HYBRID IMAGE STEGANOGRAPHY

&#x0D; &#x0D; &#x0D; A hybrid steganographic technique has been proposed to enlarge the size of secret message and to hide several images in one cover image. Initially, the secret images were compressed using JPEG 2000 before embedding them to the cover image. Second least significant bit plane of cover image was entirely replaced by secret message while tri-ways-pixel-value-differencing (TPVD) was used to hide secret message in remaining seven-bit cover image. The quality of stego image was enhanced by residual image coding (RIC). The cover image was divided in four sub-images, three of them provided cover for secret message using proposed technique while fourth sub-image was used to embed RIC of stego image using only TPVD, to ensure better quality in terms of peak signal to noise ratio (PSNR). Proposed technique provided the opportunity to transmit secret data without detection by different steganalysis techniques like dual statistics steganalysis. Experimental results verified that proposed technique achieved high payload with better image quality than TPVD scheme.&#x0D; &#x0D; &#x0D;

Advanced correlation method for bit position detection towards high accuracy data processing in industrial computer systems

Modern industrial computer systems should be reliable, noise-immune, high-speed, and error-free which is difficult due to noise and industrial interferences. In the case of single additive errors, bit insertion/dropping can occur in the outputs of demodulators which implies long error packets which are hard to correct. To provide highly reliable data transmission, parameters of bit errors exemplified by the length of insertion/dropping and position of bits have to be evaluated but widely used methods for detecting and evaluating bit errors do not yield such parameters. In this paper, two new methods are proposed as a solution to this problem for the estimation of bit error parameters under single additive errors in which the difference between two positions of clock elements in the reference sequence and the received pseudorandom sequence is calculated. The new method, in addition to algorithmic effectiveness and efficiency, makes it also possible to reduce the hardware complexity of devices to be implemented for detecting and estimating the bit error parameters. Specifically, when implemented on a specialized programmable signal processor the new approach yields the computational complexity as ∼200 + 27 T clock cycles.

High Security Image Cryptographic Algorithm Using Chaotic Encryption Algorithm with Hash-LSB Steganography

In the latest, digital images are frequently used for storage, communication, medical imaging, etc. Such images possibly involve private data, which accordingly handed an important role to information security. Image encryption and steganography are two widely used techniques for providing information security. Cryptography is the technique of protecting information by encryption and decryption. In steganography, the message is inserted in an image with changes entitled a cover image. The principal purpose of the study is to improve the current secure data communication techniques, by combining cryptography with steganography. Steganography and cryptography are two examples of the multiple methods used to guarantee secrecy and privacy throughout data communication. The suggested approach achieves encryption and decryption utilizing chaotic encryption technique and employing hash-least significant bit (HLSB) as steganography which is a significant method of embedding data bits in LSB bits of RGB pixels of the cover image. &nbsp;The suggested image encryption method is validated by experimental results to be highly secure and resistant to a variety of attacks. Additionally, compared to several conventional picture encryption techniques, it offers higher performance. Peak signal-to-noise ratio (PSNR)&nbsp;and mean square error (MSE)calculations are used to provide security evaluations. PSNR is infinite and MSE is 0 for a secret image. PSNR and MSE for the cover image are&nbsp;65 and 0.02 dB respectively. The results of this research reveal a high level of similarities between stego and cover images, and between recovered and secret images, as seen in the histogram analysis of secret images. These techniques are accomplished effectively by using the MATLAB program.

Pay Attention via Quantization: Enhancing Explainability of Neural Networks via Quantized Activation

Modern deep learning algorithms comprise highly complex artificial neural networks, making it extremely difficult for humans to track their inference processes. As the social implementation of deep learning progresses, the human and economic losses caused by inference errors are becoming increasingly problematic, making it necessary to develop methods to explain the basis for the decisions of deep learning algorithms. Although an attention mechanism-based method to visualize the regions that contribute to steering angle prediction in an automated driving task has been proposed, its explanatory capability is low. In this paper, we focus on the fact that the importance of each bit in the activation value of a network is biased (i.e., the sign and exponent bits are weighted more heavily than the mantissa bits), which has been overlooked in previous studies. Specifically, this paper quantizes network activations, encouraging important information to be aggregated to the sign bit. Further, we introduce an attention mechanism restricted to the sign bit to improve the explanatory power. Our numerical experiment using the Udacity dataset revealed that the proposed method achieves a 1.14× higher area under curve (AUC) in terms of the deletion metric.