Quantum cryptography (QC) as an important technology to protect the security of the future network communication, has gained extensive attention from both academia and industry in recent years. This paper provides a concise up-to-date review of QC, including Quantum key distribution (QKD), Quantum authentication, Quantum public-key cryptography (QPKC), and so on. Our aim is to pave a comprehensive and solid starting ground for interested readers. We firstly clarify the definition of QC. Secondly, we present the current understanding of QC from different levels, including the basic knowledge of quantum information processing, QC protocols and the attacks in QC. Finally, we discuss the challenges and opportunities in this hopeful field.

Utilizing the property of unitary transformation and Greenberger-Horne-Zeilinger (GHZ) states, a restricted quantum deniable authentication protocol is proposed. The protocol can provide that the sender can deny the content of the sent message, but cannot deny taking part in a certain communication. Security analysis results show that this protocol can satisfy known key security and the basic security requirements of restricted deniable authentication protocol such as completeness, restricted deniability, no-counterfeiting and can withstand impersonation attack, intercept-resend attack.

Quantum key distribution (QKD) technology provides proved unconditional security in pointto-point key transmissions based on quantum mechanics. However, several limitations, most prominently range, make it complex to construct large QKD network. The trusted relay QKD network is the most practical scene, and stochastic routing scheme was proposed to solve the fatal problem that some relay nodes may be controlled by adversary. But most results in stochastic routing scheme hinge on an adversary model without consideration of attacker's prior-knowledge and attack strategy. To reveal the security problem, we propose a new adversary model and apply it in grid-shaped partially-trusted relay QKD network. Then we analyze the best attack strategy and the impact on security under various situations respectively. Analysis and simulation results show that in some cases the security of stochastic routing scheme will be compromised, and a generalized upper bound for the overall safe probability is obtained. We also discuss how to alleviate the security problem, making the network more robust to attacks.

Taking the schemes based on different formulas of secure key rate as examples, we give a fair comparison between typical protocols under Universal composable (UC) security frame. Through analyzing the relationship of security parameters in post-processing stage and final secure key rate, we achieve the unified quantification between protocols based on Gottesman-Lo-Lütkenhaus-Preskill (GLLP) formula and the ones under UC security. Based on the above research, the impact of different sending lengths and secure parameters on secure key rate is investigated. Besides, we analyze the conditions of fair comparison, and for the first time we give a fair comparison between the protocols based on GLLP formula and smooth entropy. By typical efficiency comparisons, we summarize the way for improving secure key rate in the light intensity choice and the single bit error rate estimation method.

Key reconciliation is important for practical Quantum key distribution (QKD) systems since it corrects the error bits in a key string by sacrificing some key bits. Therefore, its performance directly affects the secret key rate of a practical QKD system. Although key reconciliation scheme based on polar codes can achieve a high coding efficiency, the high frame error rate causes discarding key strings and decreases the secret key rate. In this paper, we fist analyze the limitation of successive cancellation decoding of polar codes, and then we propose an improved key reconciliation scheme using polar codes with successive cancellation list decoding and optimized coding structures, which can decrease the frame error probability, resulting in a higher secret key rate. Numerical results show that the proposed scheme can achieve a 12.8% higher secret key rate than the previous polar codes-based scheme with a code length of 216 bits and a quantum bit error rate of 2%. Besides, the proposed scheme is robust and it can extract secret key bits even when the quantum bit error rate reaches 10.2% with a code length of 220 bits and a coding efficiency of 90.6%.

We propose a Quantum private query (QPQ) protocol based on device-independent Quantum key distribution (QKD) by using Einstein-Podolsky-Rosen (EPR) pairs. We analyze coherent attacks by a third party in a weaker constraints (non-signaling condition) compared with the formalism of quantum physics. We deduce the relationship between the raw key bits of Alice and the third party's attack factor. Compared with existing QPQ protocols, our protocol is secure even when the source and measuring equipment used to distribute oblivious secret key can not be trusted. Quantum register is not needed in our protocol.

The information leakage is a challenge in the design of Controlled quantum dialogue (CQD) protocols and the CQD protocol over noise channel has not been well researched. A CQD protocol without information leakage over an ideal channel is first proposed, where single photons are used to carrying secret information and pre-shared keys are used to authenticate identity and control information decoding for the prevention of information leakage, moreover, a novel kind of the unitary encoding operations with good property on the quantum operation discrimination are adopted to avoid active attacks from outside eavesdropper. By substituting logical qubits for single photons and constructing unitary encoding operations with the same property based on logical qubits, three fault-tolerant versions of the proposed CQD protocol are obtained, which can combat collective-dephasing, collective-rotation and all kinds of unitary collective noise, respectively. The security and efficiency analysis show the proposed protocols are appropriate for secure quantum dialogue in practice.

A lot of authenticated quantum dialogue protocols are springing up. Many of them have the problem of information leakage, or suffer from Man-In-The-Middle attack. Some protocols can guarantee security, but have relatively low efficiency. Based on the above situation, we present a novel authenticated quantum dialogue protocol by using Bell states and entanglement swapping. In this protocol, we adopt Einstein-Podolsky-Rosen (EPR) pairs to detect eavesdropping and transmit secret messages. We employ polarized photons to achieve authentication of users' identity information. Compared with other quantum dialogue schemes with authentication, our protocol has several advantages. The transmitted particles are passed once and do not carry any secret messages. The proposed protocol can overcome the drawback of informationleakage and resist against typical attacks. The efficiency is acceptable.

A Quantum secure direct communication (QSDC) and authentication protocol based on the W-class state is presented to enhance the efficiency of eavesdropping detection. In this protocol, the W-class state is used to transmission the checking sequence and detect eavesdroppers. In the security analysis, the method of entropy theory is introduced, and two detection strategies are compared quantitatively by using the constraint between the information that eavesdroppers can obtain and a normalized difference parameter is introduced. To obtain the same amount of information, the eavesdropper must face a higher detection probability in the proposed protocol than in the comparison. The security of the proposed protocol is also discussed. The analysis results indicate that the proposed protocol is more secure, but it must send more particles.

The relationship between Walsh transform of a Boolean function and the orthogonality of some columns of its support table is investigated. This result improves the characterization of the orthogonality of Orthogonal array (OA). Stinson and Massey gave two construction methods of linear resilient functions, one is to use linear code, the other is to utilize the large set of orthogonal arrays and right cosets. And another major contribution is to show the equivalence of two methods

The cross-correlation distribution of constant multiple sequences of the d-ary generalized Legendre- Sidelnikov sequences is investigated via character sums. An upper on the cross-correlation values of the sequences is then presented. As a byproduct, the autocorrelation distribution of d-ary Sidelnikov sequence is completely determined, which is only known in a special case.

This paper presents an attack on an encryption scheme proposed by Pei et al. using matrices over finite fields in 2010. The public information allows the derivation of a system of polynomial equations for the equivalent secret key. By the equivalent secret key, the plaintexts of the encryption scheme can be obtained by the public key and the ciphertexts without the secret key.

Proxy signature plays an important role in distributed systems, mobile agent applications, distributed shared object systems, global distribution networks and mobile communications etc., since it allows the original signer to delegate another proxy signer to sign the message instead of himself. However, the proxy signature schemes constructed on the number theory cannot resist quantum computers attack and depend on the public key infrastructure. To mitigate these problems, the alternative schemes are Identity-based proxy signature constructed on lattice. In this paper, an identity-based proxy signature scheme based on Number theorem research unit (NTRU) lattice is proposed and proven secure in the random oracle. Compared with the other existing identity-based proxy signature schemes, the proposed scheme outperforms them in terms of original signer's signature size and signing key size and proxy signer's signing key size.

Recently, how to retrieve the encrypted data efficiently from a cloud storage system becomes a hot topic. Public key encryption with keyword search (PEKS) can allow one to search the encrypted data with a keyword efficiently. Due to the booming of post-quantum cryptography, we propose public key encryption with keyword search from lattice assumption, which can resist quantum computer attacks. We delegate a particular cloud server to search the results, thus only the designated cloud server can finish the test process. Our scheme has been proved ciphertext indistinguishability in the standard model, which can reflect its security in the real world. To the best of our knowledge, our scheme is the first construction based on lattice in the standard model, which is a step stone in the post-quantum cryptographic communication.

With the proliferation of communication networks and mobile devices, Location-based services (LBSs) have brought a variety of applications and conveniences in our daily life. While LBSs greatly benefit users, they bring significant threats to users' privacy. To enhance privacy protection for LBSs, a well-used technique is to establish a collaborative group which helps each other to avoid privacy leakage. Due to extremely unbalanced system overheads for group members, many users are short of intrinsic motivations to join the collaborative group in existing schemes. To address this problem, we propose a collaborative group system combined with dummy selection technique, termed CGS-DS, which not only limits mobile users consuming significant resources in collaborative group through the hop distance, but also inspires them to generate and cache the service data of dummies for other group members. Our CGS-DS uses a threshold assignment module to generate a suitable threshold of the hop distance. While the hop distance reaches the specified threshold, the user executes the dummy-cache module to generate some dummy queries and cache the service data for other members to use. Security analysis and evaluation results indicate its effectiveness and efficiency.

A modelling method of microburst fields based on the slanted vortex-ring model was proposed. Unlike the previous vortex-ring-based model which can only generate the vertically downward microburst fields, the proposed method can produce the slanted microburst fields which are closer to the natural conditions. By setting the slant angle and the orientation angle of the slanted vortexring model, the microburst fields with any slant angle and orientation angle can be generated. A nested DE algorithm was introduced for the selection of model parameters, through which the model parameters can be flexibly and easily determined in accordance with the experimental requirements. A series of experiments were conducted and the results indicate that the proposed method can accurately and effectively generate the microburst fields.

Tissue P systems are a class of distributed and parallel computing models which are inspired from tissues. The concept of cooperation, which comes from grammar systems, is introduced into tissue P systems, by which rules in each cell are divided into several components. In each computational step, only one component of the whole tissue P system is active, and only rules belonging to this active component can be executed. Both the choice of active component and the switching between active components have several cooperating modes. The computational power of such tissue P system is proved working in several modes.

Microblog has become a major platform for people to release or obtain information. Texts on Microblog are shorter and have scarce co-occurrence information of terms. It is more complicated to discover topics from Microblog. To solve the problems, this paper proposes a dynamic author topic model FR-DATM and uses Gibbs sampling implementation for inference of this model. The FR-DATM model analyzes the relationships between blogs, and connects the related blogs to solve the sparseness of data. It allows blogs to be related to multiple topics, and each author of the blogs is also related to the topics of the blogs. The FR-DATM can also mine the topic evolution of the blogs and the authors. Experiments on Twitter dataset show that FR-DATM outperforms Latent dirichlet allocation (LDA) model and Microblog latent Dirichlet Allocation (MB-LDA) from three different perspectives: The quality of generated latent topics, the model perplexity and FR-DATM can mine the topic that the author are concerned dynamically.

In Software defined networking (SDN), distributed control plane is becoming a promising solution to tackle with scalability and performance. We propose a tree-like hierarchical routing architecture which employs the divide-and-conquer strategy to enhance routing performance on the distributed control plane. To evaluate and optimize the performance of the hierarchical architecture, we apply queuing theory to modeling routing request arrival and processing, and derive an explicit expression of the routing response time. Then we formulate the resource allocation problem in the hierarchical architecture as an optimization problem whose objective is to minimize the response time subject to queue stability and resource constraints. Using the Karush- Kuhn-Tucker (KKT) condition we obtain the optimal resource allocation policy. Based on that, we theoretically prove that the response time under the hierarchical routing architecture is strictly less than that under the Peer to peer (P2P) architecture. Finally, we perform numerical analyses to confirm the conclusions.

To solve the blocking flow shop scheduling with maximum completion time (i.e. makespan) criterion, we proposed an Improved biogeography-based optimization algorithm (IBBO). The framework of basic BBO algorithm is used in the IBBO algorithm, and the introduction of the NEH algorithm make IBBO algorithm with certain quality and diversity. The migration operation based on the insert rules and the mutation operation based on swap rules are presented to avoid the occurrence of illegal solution of the blocking flow shop problem. An insertneighborhood search algorithm was used to strengthen the local search ability of the IBBO. The computational results show the effectiveness of the proposed IBBO algorithm in solving the blocking flow shop scheduling with maximum completion time criterion.

3D CAD model retrieval plays a fundamental role in producing impressive and innovative designs easier and faster. However, after decades of efforts, effective retrieval approach for furniture models is still rare. A novel retrieval approach for furniture models, based on a hierarchical layout deduction, is proposed according to the common structure characteristics of furniture. In order to discriminate furniture models effectively both on topological, geometrical and semantic layers, special components for furniture model are defined and a multiresolution furniture model descriptor, attributed hierarchy layout graph, is adopted. To promote the retrieval efficiency, a filtering process, based on random walks method, is applied. Based on hierarchy graph matching, the similarity between two furniture models, is determined. A prototype system is implemented to verify the proposed approach effectiveness.

P system is a new kind of distributed parallel computing model, and its many variants are used to solve NP problems. All-SAT problem is a well-known NPhard problem and it has been widely applied in the fields of project selection problem, capital budgeting problem and so on. In this paper, we present a family of P systems to solve All-SAT problem in a linear time based on membrane division and give an instance to illustrate the feasibility and effectiveness of our designed P systems.

A new image interpolation method is proposed by using the image priors of nonlocal self-similarity and low rank approximation. Here the traditional cubicspline interpolation is conducted to obtain an initial High resolution (HR) image. The nonlocal similar image patches are vectorized to form data matrices with low rank prior, and thus a low rank regularization term is embedded into the reconstruction model. The texture information measured by entropy of the data matrix is extracted and used to achieve adaptive low rank approximation for retaining the latent fine details of image. The Split bregman iteration (SBI) algorithm and weighted Partial singular values thresholding (PSVT) method are adopted to obtain the optimum solution of the reconstruction model. Experimental results demonstrate the effectiveness of the proposed method in improving image quality in terms of Peak signal to noise ratio (PSNR) and/or Structural similarity (SSIM).

Gas-solid two phase flow measurements have a wide range of applications in industrial production and scientific research. Based on optical principle and image processing, a measurement method of solid phase particle size and concentration of gas-solid two phase flow was presented, and an experimental system was built. By theoretical analysis and image processing algorithms, solid phase particle sizes and concentrations in gas-solid two phase flow were achieved.

This paper proposes a novel sparse representation method for direction of arrival estimation based on dynamic dictionary and negative exponent penalty. The dynamic dictionary can eliminate the off-grid effect and the negative exponent penalty is capable of strengthening the sparse constraint to improve the performance. The basis is regarded as a part of the optimal target and the cross iteration is utilized to jointly update the dictionary and sparse support in this method. Based on the propositions of the penalty function, the penalty function is designed to replace of l ₁ norm because of its unbiasedness and stronger sparse constraint. The regularization parameter is simplified as a constant due to pre-white process, which greatly extends the application range of the proposed method. The simulation results show that the proposed method can efficiently reduce the off-grid effect and the over-complete rate of the original dictionary. Compared with the conventional sparse representation methods, it has better performance and lower computation complexity.

This work proposes a Deep neural network (DNN) based method for reconstructing speech magnitude spectrum from Mel-frequency cepstral coefficients (MFCCs). We train a DNN using MFCC vectors as input and the corresponding speech magnitude spectrum as desired output. Exploiting the strong inference power of DNN, the proposed method has the capability to accurately estimate the speech magnitude spectrum even from truncated MFCC vectors. Experiments on TIMIT corpus demonstrate that the proposed method achieves significantly better performance compared with traditional methods.

Video synopsis aims at retrieving interested events and reducing human labor on browsing long surveillance video. Traditional video synopsis methods based on energy function minimization is high computational and time consuming. Besides, the unchronological tubes shifting strategy may cause chaotic temporality and uncomfortable collisions. We propose a spatiotemporal events rearrangement optimization algorithm, which formulates the events rearrangement problem as iteration judgment on trajectory correlation and events compactability to generate the output synopsis video. An events subsection modification strategy has been presented to solve the spatial incompleteness of certain single event caused by imperfect object tracking. The experimental results have shown that the output synopsis video reserves the chronological order and avoids collisions of events.

A new unsupervised two-stage method for color image segmentation is proposed. The method contains coarse segmentation and delicate segmentation. In coarse segmentation, we adaptively choose a gray channel from CIE-lab color space. The Otsu method combined with a refinement to its threshold is applied to get global optimal segmentation. In delicate segmentation, a narrowband based procedure is applied to get more accurate contour of the object and local optimal segmentation is achieved. Our method finally balance the global optimal and the local optimal. The proposed method does not need initial contours or initial labels, thus it is more robust in certain applications. Experimental results of our method in MSRA1000 database show that our method is robust in segmenting objects and backgrounds when possessing weakly heterogeneous color. Our method firstly achieves global optimal and then achieves local optimal which draws a new and prospective outlook for segmenting color images

Practical underwater sensor networks redeployment algorithm needs to fully consider limited node resources, node move time and other characteristics in real environment. A Redeployment based on virtual forces (RBVF) algorithm is proposed. The non-persistent carrier sense multiple access protocol is introduced to solve communication conflicts between nodes during redeployment process. Based on existing study on three-dimensional space node deployment, the threshold value is determined to divide the attractive and repulsion forces. The speed of the node is considered. Simulation results indicate that the RBVF algorithm can achieve better coverage and less total move distance when moving nodes are not considered in virtual forces calculation. Water flow force is introduced, and a Virtual forces redeployment based on energy consuming (VFRBEC) algorithm is proposed, where different energy consumptions in different directions are used to modify node displacement. Simulation results indicate that the VFRBEC algorithmcan achieve the same coverage performance with the RBVF algorithm with less energy and is better than the redeployment based on combined virtual forces algorithm in terms of both coverage and energy consumption performances.

Interference can severely degrade the performance of the Global navigation satellite system (GNSS) receivers. Therefore it is important to detect the interference accurately and efficiently. Both the pre-correlation method and post-correlation method currently in use require certain strict pre-conditions, which limit their application. A new pre-correlation method that could be applied in most cases, called GNSS signal driven (GSD) method is proposed. The essence of the GSD method is to use classification techniques to detect the interference, based on the feature parameters extracted directly from the GNSS signals. The Support vector machine (SVM) and the Competitive agglomeration (CA) are adopted as the classification algorithms. When a classifier can be trained in advance, the SVM method is used, otherwise the CA method is adopted. Both methods show satisfying detection accuracy, especially the SVM method, whereas the robust CA method has an even wider application. The effectiveness of the proposed method is verified properly by experiments with the GPS L1 band Coarse/acquisition (C/A) signals.

In this paper, we propose a reconfigurable packet processing hardware architecture for future switch,in which several protocol-independent action units are introduced to remove the protocol dependence of conventional packet processors. With the proposed architecture, any specified header fields can be mapped into the right action unit, so that the processor can meet any packet processing demands. To reduce the hardware resource cost, the processor cost model and optimization algorithm are proposed. The NetFPGA-based implementation shows a throughput of 94Gb/s with 64-B packets. The programmability cost is approximately 1.5 times of conventional design, which consumes only 8% of the total FPGA resources.

The Quantum key distribution (QKD) has been entering the practical application era. The odd coherent state which follows sub Poisson distributed has been confirmed to extend transmission distance and improve secret key rate in Discrete-variable quantum key distribution (DVQKD) protocol.We propose Entanglement-based (EB) scheme of Continuous-variable quantum key distribution (CVQKD) with odd coherent state. This scheme allows distributing Gaussian modulated CVQKD with laser light which could be odd coherent state. We analyze the logarithmic negativity between entangled odd coherent states and the security. The results show that renewed scheme can extend secure distance by 10.6% and enhance the tolerance excess noise in same parameter, and the renewed scheme could be applied to prepare-and-measure (P&M) model in CVQKD.

This research investigate the information interaction protocols for Cooperative vehicleinfrastructure systems (CVIS) safety-related services and optimizes them in three aspects. It puts forward a selfadaptive back-off algorithm. This algorithm considers retransmission times and network busy degree to choose a suitable contention window. A mathematical analysis model is developed to verify its performance improvement. Finally, different scenario models of Vehicle ad hoc network (VANET) are simulated through the network simulation tool and the influences of different access modes on Quality of Service (QoS) are investigated. The simulation results have verified the improvement of the proposed algorithm is obvious and RTS/CTS access mode can sacrifice slight delay for great improvement of packet lost rate when there are large amount of vehicle nodes.