Physical Layer Encryption of OFDM-PON Based on Quantum Noise Stream Cipher with Polar Code

Orthogonal frequency division multiplexing passive optical network(OFDM-PON) has superior anti-dispersion property to operate in the C-band of fiber for increased optical power budget. However,the downlink broadcast exposes the physical layer vulnerable to the threat of illegal eavesdropping. Quantum noise stream cipher(QNSC) is a classic physical layer encryption method and well compatible with the OFDM-PON. Meanwhile, it is indispensable to exploit forward error correction(FEC) to control errors in data transmission. However, when QNSC and FEC are jointly coded, the redundant information becomes heavier and thus the code rate of the transmitted signal will be largely reduced. In this work, we propose a physical layer encryption scheme based on polar-code-assisted QNSC. In order to improve the code rate and security of the transmitted signal, we exploit chaotic sequences to yield the redundant bits and utilize the redundant information of the polar code to generate the higher-order encrypted signal in the QNSC scheme with the operation of the interleaver.We experimentally demonstrate the encrypted 16/64-QAM, 16/256-QAM, 16/1024-QAM, 16/4096-QAM QNSC signals transmitted over 30-km standard single mode fiber. For the transmitted 16/4096-QAM QNSC signal, compared with the conventional QNSC method, the proposed method increases the code rate from 0.1 to 0.32 with enhanced security.

An Improved Framework of Massive Superpoly Recovery in Cube Attacks Against NFSR-Based Stream Ciphers

A critical problem in the cube attack is how to recover superpolies efficiently.As the targeting number of rounds of an iterative stream cipher increases,the scale of its superpolies becomes larger and larger.Recently,to recover massive superpolies,the nested monomial prediction technique,the algorithm based on the divide-and-conquer strategy,and stretching cube attacks were proposed,which have been used to recover a superpoly with over ten million monomials for the NFSR-based stream ciphers such as Trivium and Grain-128AEAD.Nevertheless,when these methods are used to recover superpolies,many invalid calculations are performed,which makes recovering superpolies more difficult.This study finds an interesting observation that can be used to improve the above methods.Based on the observation,a new method is proposed to avoid a part of invalid calculations during the process of recovering superpolies.Then,the new method is applied to the nested monomial prediction technique and an improved superpoly recovery framework is presented.To verify the effectiveness of the proposed scheme,the improved framework is applied to 844-and 846-round Trivium and the exact ANFs of the superpolies is obtained with over one hundred million monomials,showing the improved superpoly recovery technique is powerful.Besides,extensive experiments on other scaled-down variants of NFSR-based stream ciphers show that the proposed scheme indeed could be more efficient on the superpoly recovery against NFSR-based stream ciphers.

General Method of Combining Grover and Simon for Attacking Block Ciphers

The compatibility of different quantum algorithms should be considered when these algorithms are combined.In this paper,the method of combining Grover and Simon is studied for the first time,under some preconditions or assumptions.First,we give two preconditions of applying Grover’s algorithm,which ensure that the success probability of finding the marked element is close to 1.Then,based on these two preconditions,it is found out that the success probability of the quantum algorithm for FXconstruction is far less than 1.Furthermore,we give the design method of the Oracle function,and then present the general method of combining Grover and Simon algorithm for attacking block ciphers,with success probability close to 1.

CS-CIPHER两个变体的线性密码分析

CS CIPHER是NESSIE公布的 17个候选算法之一 ,它的分组长度为 6 4 比特 .本文对CS CIPHER的两个变体进行了线性密码分析 .对第一个变体的攻击成功率约为 78 5 % ,数据复杂度为 2 52 ,处理复杂度为 2 3 2 .对第二个变体的攻击成功率约为 78 5 % ,数据复杂度为 2 52 ,处理复杂度为 2 112 .

How to repair the Hill cipher

The Hill cipher algorithm is one of the symmetric key algorithms that have several advantages in data encryption. However, a main drawback of this algorithm is that it encrypts identical plaintext blocks to identical ciphertext blocks and cannot encrypt images that contain large areas of a single color. Thus, it does not hide all features of the image which reveals patterns in the plaintext. Moreover, it can be easily broken with a known plaintext attack revealing weak security. This paper presents a variant of the Hill cipher that overcomes these disadvantages. The proposed technique adjusts the encryption key to form a dif- ferent key for each block encryption. Visually and computationally, experimental results demonstrate that the proposed variant yields higher security and significantly superior encryption quality compared to the original one.

THE RESEARCH AND DESIGN OF RECONFIGURABLE COMPUTING FOR BLOCK CIPHER

This paper describes a new specialized Reconfigurable Cryptographic for Block ciphersArchitecture(RCBA).Application-specific computation pipelines can be configured according to thecharacteristics of the block cipher processing in RCBA,which delivers high performance for crypto-graphic applications.RCBA adopts a coarse-grained reconfigurable architecture that mixes the ap-propriate amount of static configurations with dynamic configurations.RCBA has been implementedbased on Altera’s FPGA,and representative algorithms of block cipher such as DES,Rijndael and RC6have been mapped on RCBA architecture successfully.System performance has been analyzed,andfrom the analysis it is demonstrated that the RCBA architecture can achieve more flexibility and ef-ficiency when compared with other implementations.

An Efficient Technique to Prevent Data Misuse with Matrix Cipher Encryption Algorithms

Many symmetric and asymmetric encryption algorithms have been developed in cloud computing to transmit data in a secure form.Cloud cryptography is a data encryption mechanism that consists of different steps and prevents the attacker from misusing the data.This paper has developed an efficient algorithm to protect the data from invaders and secure the data from misuse.If this algorithm is applied to the cloud network,the attacker will not be able to access the data.To encrypt the data,the values of the bytes have been obtained by converting the plain text to ASCII.A key has been generated using the Non-Deterministic Bit Generator(NRBG)mechanism,and the key is XNORed with plain text bits,and then Bit toggling has been implemented.After that,an efficient matrix cipher encryption algorithm has been developed,and this algorithm has been applied to this text.The capability of this algorithm is that with its help,a key has been obtained from the plain text,and only by using this key can the data be decrypted in the first steps.A plain text key will never be used for another plain text.The data has been secured by implementing different mechanisms in both stages,and after that,a ciphertext has been obtained.At the end of the article,the latest technique will be compared with different techniques.There will be a discussion on how the present technique is better than all the other techniques;then,the conclusion will be drawn based on comparative analysis.

A survey on the Metaheuristics for Cryptanalysis of Substitution and Transposition Ciphers

This paper presents state-of-art cryptanalysis studies on attacks of the substitution and transposition ciphers using various metaheuristic algorithms.Traditional cryptanalysis methods employ an exhaustive search,which is computationally expensive.Therefore,metaheuristics have attracted the interest of researchers in the cryptanalysis field.Metaheuristic algorithms are known for improving the search for the optimum solution and include Genetic Algorithm,Simulated Annealing,Tabu Search,Particle Swarm Optimization,Differential Evolution,Ant Colony,the Artificial Bee Colony,Cuckoo Search,and Firefly algorithms.The most important part of these various applications is deciding the fitness function to guide the search.This review presents how these algorithms have been implemented for cryptanalysis purposes.The paper highlights the results and findings of the studies and determines the gaps in the literature.

巧用Cipher命令指定修复代理人

本文介绍了使用cipher命令,简单快速创建EFS的修复代理人的方法。其中修复代理人的指定涉及到了服务器中用户权限的升级问题,以及在服务器中关于组策略的具体使用。这些方法的使用保证了cipher命令产生的密钥能被顺利运用。

Differential Collision Attack on Reduced FOX Block Cipher

This paper presents a method for differen- tial collision attack of reduced FOX block cipher based on 4-round distinguishing property. It can be used to attack 5, 6 and 7-round FOX64 and 5-round FOX128. Our attack has a precomputation phase, but it can be obtained before attack and computed once for all. This attack on the reduced to 4-round FOX64 requires only 7 chosen plaintexts, and performs 242.8 4-round FOX64 encryptions. It could be extended to 5 （6, 7）-round FOX64 by a key exhaustive search behind the fourth round.

Improved Feistel-based ciphers for wireless sensor network security

Wireless sensor networks (WSNs) are exposed to a variety of attacks. The quality and complexity of attacks are rising day by day. The proposed work aims at showing how the complexity of modern attacks is growing accordingly, leading to a similar rise in methods of resistance. Limitations in computational and battery power in sensor nodes are constraints on the diversity of security mechanisms. We must apply only suitable mechanisms to WSN where our approach was motivated by the application of an improved Feistel scheme. The modified accelerated-cipher design uses data-dependent permutations, and can be used for fast hardware, firmware, software and WSN encryption systems. The approach presented showed that ciphers using this approach are less likely to suffer intrusion of differential cryptanalysis than currently used popular WSN ciphers like DES, Camellia and so on.

Automatic Search of Impossible Differentials and Zero-Correlation Linear Hulls for ARX Ciphers

In lightweight cryptographic primitives, round functions with only simple operations XOR, modular addition and rotation are widely used nowadays. This kind of ciphers is called ARX ciphers. For ARX ciphers, impossible differential cryptanalysis and zero-correlation linear cryptanalysis are among the most powerful attacks, and the key problems for these two attacks are discovering more and longer impossible differentials(IDs) and zero-correlation linear hulls(ZCLHs). However, finding new IDs and ZCLHs for ARX ciphers has been a manual work for a long time, which has been an obstacle in improving these two attacks. This paper proposes an automatic search method to improve the efficiency of finding new IDs and ZCLHs for ARX ciphers. In order to prove the efficiency of this new tool, we take HIGHT, LEA, SPECK three typical ARX algorithms as examples to explore their longer and new impossible differentials and zero-correlation linear hulls. To the best of our knowledge, this is the first application of automatic search method for ARX ciphers on finding new IDs and ZCLHs. For HIGHT, we find more 17 round IDs and multiple 17 round ZCLHs. This is the first discovery of 17 round ZCLHs for HIGHT. For LEA, we find extra four 10 round IDs and several 9 round ZCLHs. In the specification of LEA, the designers just identified three 10 round IDs and one 7round ZCLH. For SPECK, we find thousands of 6 round IDs and forty-four 6 round ZCLHs. Neither IDs nor ZCLHs of SPECK has been proposed before. The successful application of our new tool shows great potential in improving the impossible differential cryptanalysis and zero-correlation linear cryptanalysis on ARX ciphers..

A fast image encryption algorithm based on only blocks in cipher text

In this paper, a fast image encryption algorithm is proposed, in which the shuffling and diffusion is performed simul- taneously. The cipher-text image is divided into blocks and each block has k x k pixels, while the pixels of the plain-text are scanned one by one. Four logistic maps are used to generate the encryption key stream and the new place in the cipher image of plain image pixels, including the row and column of the block which the pixel belongs to and the place where the pixel would be placed in the block. After encrypting each pixel, the initial conditions of logistic maps would be changed ac- cording to the encrypted pixel＇s value; after encrypting each row of plain image, the initial condition would also be changed by the skew tent map. At last, it is illustrated that this algorithm has a faster speed, big key space, and better properties in withstanding differential attacks, statistical analysis, known plaintext, and chosen plaintext attacks.

Secure Video Streaming with Lightweight Cipher PRESENT in an SDN Testbed

The combination of traditional processors and Field Programmable Gate Arrays(FPGA)is shaping the future networking platform for intensive computation in resource-constrained networks and devices.These networks present two key challenges of security and resource limitations.Lightweight ciphers are suitable to provide data security in such constrained environments.Implementing the lightweight PRESENT encryption algorithm in a reconfigurable platform(FPGAs)can offer secure communication service and flexibility.This paper presents hardware acceleration of security primitives in SDN using NETFPGA-10G.We implement an efficient design of the PRESENT algorithm for faster,smaller and lower power consumption hardware circuit using Verilog.We evaluate the performance of the hardware and software implementations of PRESENT.Experimental results prove that the proposed hardware design is a viable option for use in resource constrained devices in future networks and their applications.

A novel chaotic stream cipher and its application to palmprint template protection

Based on a coupled nonlinear dynamic filter （NDF）, a novel chaotic stream cipher is presented in this paper and employed to protect palmprint templates. The chaotic pseudorandom bit generator （PRBG） based on a coupled NDF, which is constructed in an inverse flow, can generate multiple bits at one iteration and satisfy the security requirement of cipher design. Then, the stream cipher is employed to generate cancelable competitive code palmprint biometrics for template protection. The proposed cancelable palmprint authentication system depends on two factors： the palmprint biometric and the password/token. Therefore, the system provides high-confidence and also protects the user＇s privacy. The experimental results of verification on the Hong Kong PolyU Palmprint Database show that the proposed approach has a large template re-issuance ability and the equal error rate can achieve 0.02%. The performance of the palmprint template protection scheme proves the good practicability and security of the proposed stream cipher.

New State Recovery Attacks on the Grain v1 Stream Cipher

The Grain v1 stream cipher is one of the seven finalists in the final e STREAM portfolio. Though many attacks have been published,no recovery attack better than exhaustive key search on full Grain v1 in the single key setting has been found yet. In this paper,new state recovery attacks on Grain v1 utilizing the weak normality order of the employed keystream output function in the cipher are proposed. These attacks have remarkable advantages in the offline time,online time and memory complexities,which are all better than exhaustive key search. The success probability of each new attack is 0.632. The proposed attack primarily depends on the order of weak normality of the employed keystream output function. This shows that the weak normality order should be carefully considered when designing the keystream output functions of Grain-like stream ciphers.

Non-Associative Algebra Redesigning Block Cipher with Color Image Encryption

The substitution box(S-box)is a fundamentally important component of symmetric key cryptosystem.An S-box is a primary source of non-linearity in modern block ciphers,and it resists the linear attack.Various approaches have been adopted to construct S-boxes.S-boxes are commonly constructed over commutative and associative algebraic structures including Galois fields,unitary commutative rings and cyclic and non-cyclic finite groups.In this paper,first a non-associative ring of order 512 is obtained by using computational techniques,and then by this ring a triplet of 8×8 S-boxes is designed.The motivation behind the designing of these S-boxes is to upsurge the robustness and broaden the key space due to non-associative and noncommutative behavior of the algebraic structure under consideration.A novel color image encryption application is anticipated in which initially these 3 S-boxes are being used to produce confusion in three layers of a standard RGB image.However,for the sake of diffusion 3D Arnold chaotic map is used in the proposed encryption scheme.A comparison with some of existing chaos and S-box dependent color image encryption schemes specs the performance results of the anticipated RGB image encryption and observed as approaching the standard prime level.

LBC-IoT: Lightweight Block Cipher for IoT Constraint Devices

With the new era of the Internet of Things(IoT)technology,many devices with limited resources are utilized.Those devices are susceptible to a signicant number of new malware and other risks emerging rapidly.One of the most appropriate methods for securing those IoT applications is cryptographic algorithms,as cryptography masks information by eliminating the risk of collecting any meaningful information patterns.This ensures that all data communications are private,accurate,authenticated,authorized,or nonrepudiated.Since conventional cryptographic algorithms have been developed specically for devices with limited resources;however,it turns out that such algorithms are not ideal for IoT restricted devices with their current conguration.Therefore,lightweight block ciphers are gaining popularity to meet the requirements of low-power and constrained devices.A new ultra-lightweight secret-key block-enciphering algorithm named“LBC-IoT”is proposed in this paper.The proposed block length is 32-bit supporting key lengths of 80-bit,and it is mainly based on the Feistel structure.Energy-efcient cryptographic features in“LBC-IoT”include the use of simple functions(shift,XOR)and small rigid substitution boxes(4-bit-S-boxes).Besides,it is immune to different types of attacks such as linear,differential,and side-channel as well as exible in terms of implementation.Moreover,LBC-IoT achieves reasonable performance in both hardware and software compared to other recent algorithms.LBC-IoT’s hardware implementation results are very promising(smallest ever area“548”GE)and competitive with today’s leading lightweight ciphers.LBC-IoT is also ideally suited for ultra-restricted devices such as RFID tags.

Designing Pair of Nonlinear Components of a Block Cipher over Gaussian Integers

In block ciphers,the nonlinear components,also known as sub-stitution boxes(S-boxes),are used with the purpose of inducing confusion in cryptosystems.For the last decade,most of the work on designing S-boxes over the points of elliptic curves has been published.The main purpose of these studies is to hide data and improve the security levels of crypto algorithms.In this work,we design pair of nonlinear components of a block cipher over the residue class of Gaussian integers(GI).The fascinating features of this structure provide S-boxes pair at a time by fixing three parameters.But the prime field dependent on the Elliptic curve(EC)provides one S-box at a time by fixing three parameters a,b,and p.The newly designed pair of S-boxes are assessed by various tests like nonlinearity,bit independence criterion,strict avalanche criterion,linear approximation probability,and differential approximation probability.

I-PRESENT^TM: An Involutive Lightweight Block Cipher

This paper proposes a new involutive light-weight block cipher for resource-constraint environments called I-PRESENTTM. The design is based on the Present block cipher which is included in the ISO/IEC 29192 standard on lightweight cryptography. The advantage of I-PRESENTTM is that the cipher is involutive such that the encryption circuit is identical to decryption. This is an advantage for environments which require the implementation of both circuits. The area requirement of I-PRESENTTM compares reasonably well with other similar ciphers such as PRINCE.