We propose quasi ordered statistic decoding (quasi-OSD) of binary image of Reed-Solomon (RS) codes and explore the application of RS codes to joint source-channel coding (JSCC). Unlike the conventional OSD algorithms that use Gaussian elimination to obtain the systematic matrix, the proposed quasi-OSD algorithm utilizes the parallel Lagrange interpolation at the symbol level, which achieves a lower complexity and comparable performance compared with the locally constrained OSD (LC-OSD), for high-rate RS codes in the high signal-to-noise ratio (SNR) region. Additionally, we apply RS codes to the JSCC with known source statistics. At the transmitter, a new partition criterion is introduced in the classified enumerative (CE) coding to encode the source information. Then the multiple-rate RS coding transforms the variable-length codeword of the CE coding into a fixed-length transmitted codeword. At the receiver, parallel decoding is performed to recover the source. Simulation results demonstrate that the proposed JSCC scheme outperforms the double polar JSCC scheme by one dB, as expected by Gallager's JSCC bound.

In this paper, we propose a new coding scheme called dual coupled polar (DC-polar) code, which is constructed by coupling two basic polar codes. We present a successive cancellation list (SCL) decoding algorithm, where a list of candidates are generated from the first basic polar code and the most likely one is identified by combining the second basic polar code. For performance analysis and code construction, we derive lower bounds and estimate the performance by the union bounds based on the low-weight codewords. We employ the adaptive SCL decoding for DC-polar codes with early termination to reduce the decoding complexity. It is shown by numerical simulations that the proposed DC-polar codes can attain a near-capacity performance in the short-length regime.

This paper is concerned with a special class of unit memory convolutional codes (UMCCs), called block oriented UMCCs (BOUMCCs). Distinguished from conventional UMCCs, which usually have small constraint lengths, the BOUMCCs have relatively large constraint lengths. We conduct the performance analysis by assuming a first-order Markov model, which indicates that the performance of the BOUMCCs depends critically on both the error propagation and the sub-frame error rate of the first layer. The error propagation can be alleviated by the use of partial superposition, which is specified by a superposition matrix with a fraction of columns being nulled. Given a superposition fraction, we propose a tree growing and pruning algorithm (TGPA) with a tunable sliding window, which provides a convenient way to trade off the decoding delay and the performance. We also present a structured construction and show by simulation that there is no performance degradation compared with random construction. Numerical results also show that, by taking the TBCCs as basic codes, the performance of BOUMCCs with TGPA is comparable to that of other short codes but with a more flexible construction or a lower complexity.

In this paper, we propose a systematic low density generator matrix (LDGM) code ensemble, which is defined by the Bernoulli process. We prove that, under maximum likelihood (ML) decoding, the proposed ensemble can achieve the capacity of binary-input output symmetric (BIOS) memoryless channels in terms of bit error rate (BER). The proof technique reveals a new mechanism, different from lowering down frame error rate (FER), that the BER can be lowered down by assigning light codeword vectors to light information vectors. The finite length performance is analyzed by deriving an upper bound and a lower bound, both of which are shown to be tight in the high signal-to-noise ratio (SNR) region. To improve the waterfall performance, we construct the systematic convolutional LDGM (SysConv-LDGM) codes by a random splitting process. The SysConv-LDGM codes are easily configurable in the sense that any rational code rate can be realized without complex optimization. As a universal construction, the main advantage of the SysConv-LDGM codes is their near-capacity performance in the waterfall region and predictable performance in the error-floor region that can be lowered down to any target as required by increasing the density of the uncoupled LDGM codes. Numerical results are also provided to verify our analysis.

In this paper, we propose a new multi-level unequal error protection (UEP) by superposition transmission (referred to as ML-UEP-by-ST) coding scheme, which provides finer error protection abilities than the unequal error protection by partial superposition transmission (referred to as UEP-by-PST) coding scheme. This new coding scheme is then applied to video transmission with the H.265 standard, where a video bitstream can be regarded as a series of one or more groups. Each group consists of either a coded video sequence (CVS) and parameter sets or a CVS only. In the ML-UEP-by-ST system, each group of an H.265 video bitstream is partitioned equally into three parts, the most important part (Part A), the less important part (Part B) and the least important part (Part C). Each of these three parts is encoded by the same low-density parity check (LDPC) code as standardized in the fifth generation mobile networks(5G). The transmission is then formed by three sections. The first transmission is coded Part A, the second transmission is the superposition of coded Part B and the interleaved version of coded Part A, and the third transmission is the superposition of coded Part C and the interleaved version of the second transmission. Simulation results show that the performance of our proposed UEP scheme is better than the traditional equal error protection (EEP) scheme and the two-level UEP-by-PST scheme over both additive white Gaussian noise (AWGN) channels and Rayleigh fading channels.

The notion of confidential transactions plays a central role in ensuring the confidentiality of transaction amounts in a block‐chain‐based cryptocurrency. Past researches have confirmed that the access policy of transaction amounts influences the anonymity of a cryptocurrency. Most of the current techniques of confidential transactions are based on the discrete logarithm problem. Because of the threats from quantum algorithms, clients are eager to enjoy security guarantees in a post‐quantum scenario. Lattices are an ideal source of hardness, due to its exclusive worst‐case to the average‐case phenomenon. Nevertheless, the distinctions between the discrete logarithm problem and lattice problems build an obstacle in the way of borrowing the ideas from the former to the latter directly. In this study, inspired by the notion of commitments to polynomials and zero‐knowledge arguments of knowledge for the inhomogeneous short integer solution problem, the authors give an approach to implement confidential transactions using lattice techniques.

This paper is concerned with block Markov superposition transmission (BMST) of tail-biting convolutional code (TBCC). We propose a new decoding algorithm for BMST-TBCC, which integrates a serial list Viterbi algorithm (SLVA) with a soft check instead of conventional cyclic redundancy check (CRC). The basic idea is that, compared with an erroneous candidate codeword, the correct candidate codeword for the first sub-frame has less influence on the output of Viterbi algorithm for the second sub-frame. The threshold is then determined by statistical learning based on the introduced empirical divergence function. The numerical results illustrate that, under the constraint of equivalent decoding delay, the BMST-TBCC has comparable performance with the polar codes. As a result, BMST-TBCCs may find applications in the scenarios of the streaming ultra-reliable and low latency communication (URLLC) data services.

Internet of Vehicles (IoV) is the basis of future intelligent transportation systems. Both the control signaling and data dissemination services in IoV must be transmitted with high reliability and low latency so that safety can be guaranteed. Based on the discussion and analyses of issues in achieving high reliability low latency transmissions, we present in this paper a Polar code-based overlapping transmission scheme in which simultaneous transmissions from different nodes to the same receiving node are allowed to use the same time-frequency resource block. To effectively eliminate multiple access interference introduced by the overlapped nonorthogonal transmissions, a successive cancellation list-based improved interference elimination decoding algorithm (SCL-based IIEDA) is proposed to retrieve the Polar coded information. Numerical results show that the SCL-based IIEDA performs well on information recovery in the presented transmission scheme. In addition, it is shown that the proposed scheme not only significantly reduces the acknowledgment overhead but also greatly improves the spectral efficiency.

This paper is concerned with three ensembles of systematic low density generator matrix (LDGM) codes, all of which were provably capacity-achieving in terms of bit error rate (BER). This, however, does not necessarily imply that they achieve the capacity in terms of frame error rate (FER), as seen from a counterexample constructed in this paper. We then show that the first and second ensembles are capacity-achieving under list decoding over binary-input output symmetric (BIOS) memoryless channels. We point out that, in principle, the equivocation due to list decoding can be removed with negligible rate loss by the use of the concatenated codes. Simulation results show that the considered convolutional (spatially-coupled) LDGM code is capacity-approaching with an iterative belief propagation decoding algorithm.

Abstract Blind signature is a crucial technique to provide anonymity in many information systems such as e‐cash, e‐voting, and smart grid systems. Partially blind signature is a more applicable extension where the part of the message includes some common information known by the signer and the signature requestor. In the family of lattice‐based schemes, blind signatures are given in ASIACRYPT 2010 by R ckert in the random oracle model, and until now, no partially blind signatures are given. We here design the first scheme based on Lyubashevsky's signature scheme in EUROCRYPT 2012 and Abe and Okamoto's construction of partially blind signature in CRYPTO 2000 in the random oracle model. The scheme shows an alternative approach to achieve the blindness property without the supports of a commitment scheme and of a final round communication to confirm the validity of a signature. Copyright © 2016 John Wiley & Sons, Ltd.

Abstract An on‐line/off‐line threshold signature (𝒪𝒯𝒮) scheme is a distributed cryptosystem in which a group of players jointly generate a signature for a message and use the on‐line/off‐line technique to improve the efficiency of signing. An 𝒪𝒯𝒮 scheme can be applied to large‐scaled distributed data storage systems and can highly improve the efficiency of writing files. There are two approaches to construct an ordinary threshold signature scheme: the direct approach and the simulation approach. Owing to its simplicity, people tend to use the simulation approach, in which the security of a threshold signature scheme is reduced to the security of its underlying (and simpler) signature scheme. The security proof in this approach is based on a theorem that guarantees the validity of the security reduction—we call this theorem the simulation theorem. However, the simulation theorem (and thus the simulation approach) for an ordinary threshold signature scheme cannot be applied to the on‐line/off‐line cases, because partial signature exposure problems might occur in these cases. This paper presents a simulation theorem for the on‐line/off‐line cases, where the security of an 𝒪𝒯𝒮 scheme is reduced to the security of a so‐called divisible on‐line/off‐line signature scheme. This provides a theoretical basis for constructing an 𝒪𝒯𝒮 scheme through the simulation approach. Furthermore, through this approach, we present a concrete 𝒪𝒯𝒮 scheme, which is efficient and its security proof is simple. Copyright © 2009 John Wiley & Sons, Ltd.

Designated confirmer signature is an important cryptographic primitive, it is widely used in E-commerce. In this paper, we propose a new designated confirmer signature scheme which is transformed from a new signature scheme. The proposed scheme has very simple construction and is much more efficient than the previous ones and does not need any commitment scheme or strong witness hiding proofs.

In this paper, by combining the functionalities of proxy signatures and ring signatures, we propose a new concept, named ring proxy signature, which is a proxy signature generated by an anonymous member from a set of potential signers. We construct two ID-based ring proxy signature schemes. The security analysis is provided as well.

It is well known that the algebraic expression of the advanced encryption standard (AES) Rijndael S-box is very simple and only 9 terms are involved. In this paper a new algebraic method is proposed to illustrate the reason why AES S-box algebraic expression is very simple, which corrects all the available inaccurate illustrations. An improved AES S-box is also presented to improve the complexity of AES S-box algebraic expression with terms increasing from 9 to 255 and algebraic degree invariable. The improved AES S-box also has good properties of Boolean functions in SAC and balance, and is capable of attacking against differential cryptanalysis with high reliable security.

There have not been many successful attacks against the AES algorithm Rijndael so far, of which the best known and effective attack is the Square Attack. It takes advantage of the balance property of the algorithm. A new type of attack which makes use of the activity property is proposed. The consuming time and chosen plaintexts necessary are both reduced to one tenth of the original ones. The analysis principle is described.

The general autocorrelation proposed is the extension of the traditional autocorrelation. Besides having the same ability as autocorrelation to reveal the characteristics of the linear structures, the strict avalanche criterion (SAC) and the propagation criterion (PC) of degree k, the general autocorrelation is capable of finding the order of SAC and PC which is a capability that autocorrelation does not possess. The application on AES S-box shows the SAC and PC characteristics of the eight AES Boolean functions.