Minimizing the Two-Round Even–Mansour Cipher

The r-round (iterated) Even–Mansour cipher (also known as key-alternating cipher) defines a block cipher from r fixed public n-bit permutations \(P_1,\ldots ,P_r\) as follows: Given a sequence of n-bit round keys \(k_0,\ldots ,k_r\), an n-bit plaintext x is encrypted by xoring round key \(k_0\), applying permutation \(P_1\), xoring round key \(k_1\), etc. The (strong) pseudorandomness of this construction in the random permutation model (i.e., when the permutations \(P_1,\ldots ,P_r\) are public random permutation oracles that the adversary can query in a black-box way) was studied in a number of recent papers, culminating with the work of Chen and Steinberger (EUROCRYPT 2014), who proved that the r-round Even–Mansour cipher is indistinguishable from a truly random permutation up to \(\mathcal {O}(2^{\frac{rn}{r+1}})\) queries of any adaptive adversary (which is an optimal security bound since it matches a simple distinguishing attack). All results in this entire line of work share the common restriction that they only hold under the assumption that the round keys \(k_0,\ldots ,k_r\) and the permutations \(P_1,\ldots ,P_r\) are independent. In particular, for two rounds, the current state of knowledge is that the block cipher \(E(x)=k_2\oplus P_2(k_1\oplus P_1(k_0\oplus x))\) is provably secure up to \(\mathcal {O}(2^{2n/3})\) queries of the adversary, when \(k_0\), \(k_1\), and \(k_2\) are three independent n-bit keys, and \(P_1\) and \(P_2\) are two independent random n-bit permutations. In this paper, we ask whether one can obtain a similar bound for the two-round Even–Mansour cipher from just one n-bit key and one n-bit permutation. Our answer is positive: When the three n-bit round keys \(k_0\), \(k_1\), and \(k_2\) are adequately derived from an n-bit master key k, and the same permutation P is used in place of \(P_1\) and \(P_2\), we prove a qualitatively similar \(\widetilde{\mathcal {O}}(2^{2n/3})\) security bound (in the random permutation model). To the best of our knowledge, this is the first “beyond the birthday bound” security result for AES-like ciphers that does not assume independent round keys.     

Error performance of optically preamplified hybrid BPSK-PPM systems with transmitter and receiver imperfections

In this paper, we investigate the impact of the transmitter finite extinction ratio and the receiver carrier recovery phase offset on the error performance of two optically preamplified hybrid M-ary pulse position modulation (PPM) systems with coherent detection. The first system, referred to as PB-mPPM, combines polarization division multiplexing (PDM) with binary phase-shift keying and M-ary PPM, and the other system, referred to as PQ-mPPM, combines PDM with quadrature phase-shift keying and M-ary PPM. We provide new expressions for the probability of bit error for PB-mPPM and PQ-mPPM under finite extinction ratios and phase offset. The extinction ratio study indicates that the coherent systems PB-mPPM and PQ-mPPM outperform the direct-detection ones. It also shows that at \(P_b=10^{-9}\) PB-mPPM has a slight advantage over PQ-mPPM. For example, for a symbol size \(M=16\) and extinction ratio \(r=30\) dB, PB-mPPM requires 0.6 dB less SNR per bit than PQ-mPPM to achieve \(P_b=10^{-9}\). This investigation demonstrates that PB-mPPM is less complex and less sensitive to the variations of the offset angle \(\theta \) than PQ-mPPM. For instance, for \(M=16\), \(r=30\) dB, and \(\theta =10^{\circ }\) PB-mPPM requires 1.6 dB less than PQ-mPPM to achieve \(P_b=10^{-9}\). However, PB-mPPM enhanced robustness to phase offset comes at the expense of a reduced bandwidth efficiency when compared to PQ-mPPM. For example, for \(M=2\) its bandwidth efficiency is 60 % that of PQ-mPPM and \(\approx 86\,\%\) for \(M=1024\). For these reasons, PB-mPPM can be considered a reasonable design trade-off for M-ary PPM systems.     

Relay selection in mixed RF/FSO system using DF relaying

In this paper, we carry out the performance analysis of relay selection in decode-and-forward (DF)-based mixed radio frequency/free-space optical (RF/FSO) system. We consider two relay selection schemes, namely max-select and distributed switch and stay, and compare their performance with the system having all relays active. The selected DF relay decodes the received RF signal from source and converts it into an optical signal using the subcarrier intensity modulation scheme for transmission over FSO links. The RF links follow generalized \(\eta -\mu \) distribution, while the FSO links are subjected to pointing errors and are assumed to follow gamma–gamma distribution. Novel analytical expressions for cumulative density function and the moment generating function of the equivalent end-to-end signal-to-noise ratio are derived. Capitalizing on the derived statistics, we provide the new closed-form expressions of the outage probability for different relay selection schemes.     

An Investigation of Massive Gain in Hybrid Configurable Cylindrical Dielectric Resonator Antenna

Delay Tolerant Networks (DTNs) have attracted various interests these days. Since DTNs are subject to high loss rate, large delay, intermittent connection, and even no end-to-end connectivity, relay nodes, such as throwboxes, are deployed to enhance network performance. Internet-based systems have contemporaneous connectivity between location-distributed nodes, and this does not apply to DTNs. Thus, the traditional relay node deployment strategies are no longer suitable for DTNs. In this paper, we propose a novel strategy, named Connection-2 (\(CO_2\)), to deploy throwboxes to enhance the fault tolerance of DTNs. \(CO_2\) constructs a 2-connected DTN using an approximation algorithm. Every mobile node in the 2-connected DTN can reach another mobile node via two or more node-disjoint paths within its mobility range. While enhancing fault tolerance, the number of throwboxes that \(CO_2\) requires is small. We conduct various experiments based on the simulation of the real Tuscaloosa bus transit system and compare its performance with two popular strategies. Experimental results show that \(CO_2\) is effective.     

Electrical Transport Mechanisms and Photoconduction in Undoped Crystalline Flash-Evaporated Lead Iodide Thin Films

The flash-evaporation technique was utilized to fabricate undoped 1.35-μm and 1.2-μm thick lead iodide films at substrate temperatures \( T_{\rm{s}} = 150 \)°C and 200°C, respectively. The films were deposited onto a coplanar comb-like copper (Cu-) electrode pattern, previously coated on glass substrates to form lateral metal–semiconductor–metal (MSM-) structures. The as-measured constant-temperature direct-current (dc)-voltage (\( I\left( {V;T} \right) - V \)) curves of the obtained lateral coplanar Cu-PbI₂-Cu samples (film plus electrode) displayed remarkable ohmic behavior at all temperatures (\( T = 18 - 90\,^\circ {\hbox{C}} \)). Their dc electrical resistance \( R_{\rm{dc}} (T \)) revealed a single thermally-activated conduction mechanism over the temperature range with activation energy \( E_{\rm{act}} \approx 0.90 - 0.98 \,{\hbox{eV}} \), slightly less than half of room-temperature bandgap energy \( E_{\rm{g}} \) (\( \approx \,2.3\, {\hbox{eV}} \)) of undoped 2H-polytype PbI₂ single crystals. The undoped flash-evaporated \( {\hbox{PbI}}_{\rm{x}} \) thin films were homogeneous and almost stoichiometric (\( x \approx 1.87 \)), in contrast to findings on lead iodide films prepared by other methods, and were highly crystalline hexagonal 2H-polytypic structure with c-axis perpendicular to the surface of substrates maintained at \( T_{\rm{s}} { \gtrsim }150^\circ {\hbox{C}} \). Photoconductivity measurements made on these lateral Cu-PbI₂-Cu-structures under on–off visible-light illumination reveal a feeble photoresponse for long wavelengths (\( \lambda > 570\,{\hbox{nm}} \)), but a strong response to blue light of photon energy \( E_{\rm{ph}} \) \( \approx \,2.73 \, {\hbox{eV}} \) (\( > E_{\rm{g}} \)), due to photogenerated electron–hole (e–h) pairs via direct band-to-band electronic transitions. The constant-temperature/dc voltage current–time \( I\left( {T,V} \right) - t \) curves of the studied lateral PbI₂ MSM-structures at low ambient temperatures (\( T < 50^\circ {\hbox{C}} \)), after cutting off the blue-light illumination, exhibit two trapping mechanisms with different relaxation times. These strongly depend on \( V \) and \( T \), with thermally generated charge carriers in the PbI₂ mask photogenerated (e–h) pairs at higher temperatures.     

Performance analysis of MIMO–OFDM free space optical communication system with low-density parity-check code

In this paper, we have evaluated the performance of a low-density parity-check (LDPC)-coded multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) free space optical (FSO) communication system. Closed form expressions for the average bit error rate and throughput with diversity using equal gain combining have been obtained for the system under consideration. The Monte Carlo simulation has been carried out for the verification of the results. The performance of the QPSK and 16 QAM modulations is evaluated for different weather and atmospheric turbulence conditions. The results are also compared for both, QPSK and 16 QAM for SISO–OFDM, \(2\times 2\) and \(4 \times 4\) MIMO–OFDM FSO communication system. The results show that the performance of the system under consideration improves, as we move from SISO–OFDM to \(4 \times 4\) MIMO–OFDM. The results also show that the effect of weather is very much pronounced on the system and the performance in terms of average bit error rate of QPSK is better than 16 QAM in the presence of every weather condition. However, the later provides better throughput. Regular LDPC codes with code rate 1/2 have been applied to the simulated results, yielding high coding gains. Coding gain of 29.5 and 22 dB is achieved for QPSK and 16 QAM, respectively, for \(4 \times 4\) MIMO–OFDM.     

Automata Evaluation and Text Search Protocols with Simulation-Based Security

This paper presents efficient protocols for securely computing the following two problems: (1) The fundamental problem of pattern matching. This problem is defined in the two-party setting, where party \(P_1\) holds a pattern and party \(P_2\) holds a text. The goal of \(P_1\) is to learn where the pattern appears in the text, without revealing it to \(P_2\) or learning anything else about \(P_2\)’s text. This problem has been widely studied for decades due to its broad applicability. We present several protocols for several notions of security. We further generalize one of our solutions to solve additional pattern matching-related problems of interest. (2) Our construction from above, in the malicious case, is based on a novel protocol for secure oblivious automata evaluation which is of independent interest. In this problem, party \(P_1\) holds an automaton and party \(P_2\) holds an input string, and they need to decide whether the automaton accepts the input, without learning anything else. Our protocol obtains full security in the face of malicious adversaries.     

A 11.2 mW 48–62 GHz Low Noise Amplifier in 65 nm CMOS Technology

In this paper, a wideband low noise amplifier (LNA) for 60 GHz wireless applications is presented. A single-ended two-stage cascade topology is utilized to realize an ultra-wideband and flat gain response. The first stage adopts a current-reused topology that performs the more than 10 GHz ultra-wideband input impedance matching. The second stage is a cascade common source amplifier that is used to enhance the overall gain and reverse isolation. By proper optimization of the current-reused topology and stagger turning technique, the two-stage cascade common source LNA provides low power consumption and gain flatness over an ultra-wide frequency band with relatively low noise. The LNA is fabricated in Global Foundries 65 nm RFCMOS technology. The measurement results show a maximum \(S_{21}\) gain of 11.4 dB gain with a \(-\)3 dB bandwidth from 48 to 62 GHz. Within this frequency range, the measured \(S_{11}\) and \(S_{12}\) are less than \(-\)10 dB and the measured DC power consumption is only 11.2 mW from a single 1.5 V supply.     

Design and Performance Study of Dynamic Fractors in Any of the Four Quadrants

A fractor is a simple fractional-order system. Its transfer function is \(1/Fs^{\alpha }\); the coefficient, F, is called the fractance, and \(\alpha \) is called the exponent of the fractor. This paper presents how a fractor can be realized, using RC ladder circuit, meeting the predefined specifications on both F and \(\alpha \). Besides, commonly reported fractors have \(\alpha \) between 0 and 1. So, their constant phase angles (CPA) are always restricted between \(0^{\circ }\) and \(-90^{\circ }\). This work has employed GIC topology to realize fractors from any of the four quadrants, which means fractors with \(\alpha \) between \(-\)2 and +2. Hence, one can achieve any desired CPA between \(+180^{\circ }\) and \(-180^{\circ }\). The paper also exhibits how these GIC parameters can be used to tune the fractance of emulated fractors in real time, thus realizing dynamic fractors. In this work, a number of fractors are developed as per proposed technique, their impedance characteristics are studied, and fractance values are tuned experimentally.     

5.18–7.42 GHz LC-VCO in subthreshold regime with low power low phase noise and immunity to PVT variations in 130 nm CMOS technology

In this paper, we propose an LC-VCO using automatic amplitude control and filtering technique to eliminate frequency noise around 2\(\omega _0\). The LC-VCO is designed with TSMC 130 nm CMOS RF technology, and biased in subthreshold regime in order to get more negative transconductance to overcome the losses in the LC-Tank and achieve less power consumption. The designed VCO operates at 5.17 GHz and can be tuned from 5.17 to 7.398 GHz, which is corresponding to 35.5% tuning range. The VCO consumes through it 495–440.5 \(\upmu\)W from 400 mV dc supply. This VCO achieves a phase noise of \(-\,122.3\) and \(-\,111.7\) dBc/Hz at 1 MHz offset from 5.17 and 7.39 GHz carrier, respectively. The calculated Figure-of-merits (FoM) at 1 MHz offset from 5.17 and 7.39 GHz is \(-\,199.7\) and \(-\,192.4\) dBc/Hz, respectively. And it is under \(-\,190.5\) dBc/Hz through all the tuning range. The FoM\(_T\) at 1 MHz offset from 5.17 GHz carrier is \(-\,210.6\) dBc/Hz. The proposed design was simulated for three different temperatures (\(-\,55\), 27, \(125\,^{\circ }\hbox {C}\)), and three supply voltages (0.45, 0.4, 0.35 V), it was concluded that the designed LC-VCO presents high immunity to PVT variations, and can be used for multi-standard wireless LAN communication protocols 802.11a/b/g.     

A novel optimized neutrosophic <Emphasis Type="Italic">k</Emphasis>-means using genetic algorithm for skin lesion detection in dermoscopy images

This paper implemented a new skin lesion detection method based on the genetic algorithm (GA) for optimizing the neutrosophic set (NS) operation to reduce the indeterminacy on the dermoscopy images. Then, k-means clustering is applied to segment the skin lesion regions. Therefore, the proposed method is called optimized neutrosophic k-means (ONKM). On the training images set, an initial value of \(\alpha \) in the \(\alpha \)-mean operation of the NS is used with the GA to determine the optimized \(\alpha \) value. The Jaccard index is used as the fitness function during the optimization process. The GA found the optimal \(\alpha \) in the \(\alpha \)-mean operation as \(\alpha _{\mathrm{optimal}} =0.0014\) in the NS, which achieved the best performance using five fold cross-validation. Afterward, the dermoscopy images are transformed into the neutrosophic domain via three memberships, namely true, indeterminate, and false, using \(\alpha _{\mathrm{optimal}}\). The proposed ONKM method is carried out to segment the dermoscopy images. Different random subsets of 50 images from the ISIC 2016 challenge dataset are used from the training dataset during the fivefold cross-validation to train the proposed system and determine \(\alpha _{\mathrm{optimal}}\). Several evaluation metrics, namely the Dice coefficient, specificity, sensitivity, and accuracy, are measured for performance evaluation of the test images using the proposed ONKM method with \(\alpha _{\mathrm{optimal}} =0.0014\) compared to the k-means, and the \(\gamma \)–k-means methods. The results depicted the dominance of the ONKM method with \(99.29\pm 1.61\%\) average accuracy compared with k-means and \(\gamma \)–k-means methods.     

Efficient Slide Attacks

The slide attack, presented by Biryukov and Wagner, has already become a classical tool in cryptanalysis of block ciphers. While it was used to mount practical attacks on a few cryptosystems, its practical applicability is limited, as typically, its time complexity is lower bounded by \(2^n\) (where n is the block size). There are only a few known scenarios in which the slide attack performs better than the \(2^n\) bound. In this paper, we concentrate on efficient slide attacks, whose time complexity is less than \(2^n\). We present a number of new attacks that apply in scenarios in which previously known slide attacks are either inapplicable, or require at least \(2^n\) operations. In particular, we present the first known slide attack on a Feistel construction with a 3-round self-similarity, and an attack with practical time complexity of \(2^{40}\) on a 128-bit key variant of the GOST block cipher with unknown S-boxes. The best previously known attack on the same variant, with known S-boxes (by Courtois), has time complexity of \(2^{91}\).     

Comparison of $$(1+\alpha )$$ Fractional-Order Transfer Functions to Approximate Lowpass Butterworth Magnitude Responses

Three fractional-order transfer functions are analyzed for differences in realizing (\(1+\alpha \)) order lowpass filters approximating a traditional Butterworth magnitude response. These transfer functions are realized by replacing traditional capacitors with fractional-order capacitors (\(Z=1/s^{\alpha }C\) where \(0\le \alpha \le 1\)) in biquadratic filter topologies. This analysis examines the differences in least squares error, stability, \(-\)3 dB frequency, higher-order implementations, and parameter sensitivity to determine the most suitable (\(1+\alpha \)) order transfer function for the approximated Butterworth magnitude responses. Each fractional-order transfer function for \((1+\alpha )=1.5\) is realized using a Tow–Thomas biquad a verified using SPICE simulations.     

Aggregation defragmentation algorithm based on channel density and minimum gap in elastic optical networks

Free-space optics (FSO) is a data relaying technology, which requires a direct line of sight between the transmitter and the receiver units for reliable transmission. FSO communication links have many merits such as high modulation bandwidth, high data transmission rates, low cost, and easy installation process. The performance of FSO link is affected by certain external parameters such as absorption, scintillation, and atmospheric attenuation due to different weather conditions. This paper reports the designing and simulative comparison of two wavelength division multiplexing-based FSO links under rain and snow weather conditions. The proposed system reports successful transmission of \(32\times 10\) Gbps of data along a link distance of 16.5 and 1.07 km under rain and snow weather conditions, respectively, with acceptable performance levels (\(Q\sim \) 6 dB and \(\hbox {BER} \le 10^{-9}\)).     

The Security of Tandem-DM in the Ideal Cipher Model

We prove that Tandem-DM, one of the two “classical” schemes for turning an n-bit blockcipher of 2n-bit key into a double-block-length hash function, has birthday-type collision resistance in the ideal cipher model. For \(n=128\), an adversary must make at least \(2^{120.87}\) blockcipher queries to achieve chance 0.5 of finding a collision. A collision resistance analysis for Tandem-DM achieving a similar birthday-type bound was already proposed by Fleischmann, Gorski and Lucks at FSE 2009. As we detail, however, the latter analysis is wrong, thus leaving the collision resistance of Tandem-DM as an open problem until now. Our analysis exhibits a novel feature in that we introduce a trick never used before in ideal cipher proofs. We also give an improved bound on the preimage security of Tandem-DM. For \(n=128\), we show that an adversary must make at least \(2^{245.99}\) blockcipher queries to achieve chance 0.5 of inverting a randomly chosen point in the range. Asymptotically, Tandem-DM is proved to be preimage resistant up to \(2^{2n}/n\) blockcipher queries. This bound improves upon the previous best bound of \({{\varOmega }}(2^n)\) queries and is optimal (ignoring log factors) since Tandem-DM has range of size \(2^{2n}\).     

Locally Computable UOWHF with Linear Shrinkage

We study the problem of constructing locally computable universal one-way hash functions (UOWHFs) \(\mathcal {H}:\{0,1\}^n \rightarrow \{0,1\}^m\). A construction with constant output locality, where every bit of the output depends only on a constant number of bits of the input, was established by Applebaum et al. (SIAM J Comput 36(4):845–888, 2006). However, this construction suffers from two limitations: (1) it can only achieve a sublinear shrinkage of \(n-m=n^{1-\epsilon }\) and (2) it has a super-constant input locality, i.e., some inputs influence a large super-constant number of outputs. This leaves open the question of realizing UOWHFs with constant output locality and linear shrinkage of \(n-m= \epsilon n\), or UOWHFs with constant input locality and minimal shrinkage of \(n-m=1\). We settle both questions simultaneously by providing the first construction of UOWHFs with linear shrinkage, constant input locality and constant output locality. Our construction is based on the one-wayness of “random” local functions—a variant of an assumption made by Goldreich (Studies in Complexity and Cryptography, 76–87, 2011; ECCC 2010). Using a transformation of Ishai et al. (STOC, 2008), our UOWHFs give rise to a digital signature scheme with a minimal additive complexity overhead: signing n-bit messages with security parameter \(\kappa \) takes only \(O(n+\kappa )\) time instead of \(O(n\kappa )\) as in typical constructions. Previously, such signatures were only known to exist under an exponential hardness assumption. As an additional contribution, we obtain new locally computable hardness amplification procedures for UOWHFs that preserve linear shrinkage.     

A Dichotomy for Local Small-Bias Generators

We consider pseudorandom generators in which each output bit depends on a constant number of input bits. Such generators have appealingly simple structure: They can be described by a sparse input–output dependency graph \(G\) and a small predicate \(P\) that is applied at each output. Following the works of Cryan and Miltersen (MFCS’01) and by Mossel et al (STOC’03), we ask: which graphs and predicates yield “small-bias” generators (that fool linear distinguishers)? We identify an explicit class of degenerate predicates and prove the following. For most graphs, all non-degenerate predicates yield small-bias generators, \(f:\{0,1\}^n \rightarrow \{0,1\}^m\), with output length \(m = n^{1 + \epsilon }\) for some constant \(\epsilon > 0\). Conversely, we show that for most graphs, degenerate predicates are not secure against linear distinguishers, even when the output length is linear \(m=n+\Omega (n)\). Taken together, these results expose a dichotomy: Every predicate is either very hard or very easy, in the sense that it either yields a small-bias generator for almost all graphs or fails to do so for almost all graphs. As a secondary contribution, we attempt to support the view that small-bias is a good measure of pseudorandomness for local functions with large stretch. We do so by demonstrating that resilience to linear distinguishers implies resilience to a larger class of attacks.     

Stabilization of Discrete-time Fuzzy Systems Via Delta Operators and its Application to Truck–Trailer Model

This paper addresses the problem of robust \(L_2{-}L_\infty \) control in delta domain for a class of Takagi–Sugeno (TS) fuzzy systems with interval time-varying delays and disturbance input. In particular, the system under study involves state time delay, uncertainties and fast sampling period \(\mathcal {T}\). The main aim of this work was to design a \(L_2{-}L_\infty \) controller such that the proposed TS fuzzy system is robustly asymptotically stable with a \(L_2{-}L_\infty \) prescribed performance level \(\gamma >0\). Based on the proper Lyapunov–Krasovskii functional (LKF) involving lower and upper bound of time delay and free-weighting technique, a new set of delay-dependent sufficient conditions in terms of linear matrix inequalities (LMIs) are established for obtaining the required result. The result reveals that the asymptotic stability is achieved quickly when the sampling frequency is high. Finally, a numerical example based on the truck–trailer model is given to demonstrate the effectiveness and potential of the proposed design technique.     

On the equivalence of multivariate polynomial matrices

The equivalence of system is an important concept in multidimensional (\(n\)D) system, which is closely related to equivalence of multivariate polynomial matrices. This paper mainly investigates the equivalence of some \(n\)D polynomial matrices, several new results and conditions on the reduction by equivalence of a given \(n\)D polynomial matrix to its Smith form are obtained.     

Intermittent Fault Diagnosability of Hyper Petersen Network

The problem of permanent fault diagnosis has been discussed widely, and the diagnosability of many well-known networks have been explored. Faults of a multiprocessor system generally include permanent and intermittent, with intermittent faults regarded as the most challenging to diagnose. In this paper, we investigate the intermittent fault diagnosability of hyper Petersen networks. First, we derive that an \(n\)-dimensional hyper Petersen network \(HP_{n}\) with fault-free edges is \((n - 1)_{i}\)-diagnosable under the PMC model. Then, we investigate the intermittent fault diagnosability of \(HP_{n}\) with faulty edges under the PMC model. Finally, we prove that an \(n\)-dimensional hyper Petersen network \(HP_{n}\) is \((n - 2)_{i}\)-diagnosable under the MM* model.