Problems In Cryptography Research Articles

Never lost keys: A novel key generation scheme based on motor imagery EEG in end-edge-cloud system

Biometric key is generated from the user's unique biometric features, and can effectively solve the security problems in cryptography. However, the current prevailing biometric key generation techniques such as fingerprint recognition and facial recognition are poor in randomness and can be forged easily. According to the characteristics of Electroencephalographic(EEG) signals such as the randomness, nonlinear and non-stationary etc., it can significantly avoid these flaws. This paper proposes a novel method to generate keys based on EEG signals with end-edge-cloud collaboration computing. Using sensors to measure motor imagery EEG data, the key is generated via pre-processing, feature extraction and classification. Experiments show the total time consumption of the key generation process is about 2.45s. Our scheme is practical and feasible, which provides a research route to generate biometric keys using EEG data.

Deep Learning-Based Cryptanalysis of a Simplified AES Cipher

Recently, Deep Neural Networks have shown great deal of reliability and applicability as its applications spread in different areas. This paper proposes a cryptanalysis model based on Deep Neural Network, the neural network takes in plaintexts and their corresponding ciphertexts to predict the secret key of the cipher. We proposes two different approaches, in the first we use multi-layer perceptron (MLP). While in the second, the cryptanalysis problem is modeled as a multi-label classification problem, we introduce appropriate Deep Neural Network based methods for tackling such problem. We illustrate the effectiveness of the approach of the DNN-based cryptanalysis by attacking on Simplified AES block cipher. Therefore, specific metrics are readapted to the cryptanalysis context and used to evaluate the proposed schemes. The results indicate that treating cryptanalysis problem as multi-label classification is more suitable and can be a useful and promising tool for the cryptanalysis task.

On New Problems in Asymmetric Cryptography Based on Error-Resistant Coding

On New Problems in Asymmetric Cryptography Based on Error-Resistant Coding

Cryptocurrencies’ hashrate and electricity consumption: evidence from mining activities

PurposeGiven the growing importance of cryptocurrencies and the technique called “SegWit” that allows to compile more transactions in a mined block, the electricity consumed per block might potentially decrease. The purpose of this study is to consider that the difficulty to mine a block might be a better indicator of the Bitcoin\\Ether’s electricity consumption.Design/methodology/approachThis study applies the vector error correction model to investigate data related to primary energy consumption and electricity production, supply and consumption for Bitcoin and Ether hashrates from 2016M1 to 2021M5.FindingsThe hashrate (difficulty of solving the cryptographic problem related to the validation of a transaction) is found to have a positive cointegration with energy and electricity consumption. Despite the launch of the Segregation Witness (SegWit) mechanism allowing blocks to handle a higher number of transactions per block, this Bitcoin and Ether growing need in electricity has significantly been increasing since October 2019.Originality/valueThe major contribution of this study is to investigate a more relevant indicator, namely, hashrate (computational difficulty to solve cryptographic enigma associated with cryptocurrencies-related transaction). The approach of this study can be justified by the fact that there exists a technical solution consisting in increasing the number of transactions per blocks so that less electricity might be required to validate a transaction.

Converting of Boolean Expression to Linear Equations, Inequalities and QUBO Penalties for Cryptanalysis

There exists a wide range of constraint programming (CP) problems defined on Boolean functions depending on binary variables. One of the approaches to solving CP problems is using specific appropriate solvers, e.g., SAT solvers. An alternative is using the generic solvers for mixed-integer linear programming problems (MILP), but they require transforming expressions with Boolean functions to linear equations or inequalities. Here, we present two methods of such a transformation which applies to any Boolean function defined by explicit rules giving values of the Boolean function for all combinations of its Boolean variables. The first method represents the Boolean function as a linear equation in the original binary variables and, possibly, binary ancillaries, which become additional variables of the MILP problem being composed. The second method represents the Boolean function as a set of linear inequalities in the original binary variables and one additional continuous variable (representing the value of the function). The choice between the first or second method is a trade-off between the number of binary variables and number of linear constraints in the emerging MP problem. The advantage of the proposed approach is that both methods reduce important cryptanalysis problems, such as the preimaging of hash functions or breaking symmetric ciphers as the MILP problems, which are solved by the generic MILP solvers. Furthermore, the first method enables to reduce the binary linear equations to quadratic unconstrained binary optimization (QUBO), by the quantum annealer, e.g., D-Wave.

Design Principles of Secure Certificateless Signature and Aggregate Signature Schemes for IoT Environments

Certificateless cryptography resolves the certificate management problem of public-key cryptography and the key-escrow problem of identity-based cryptography. An aggregate signature scheme which allows to aggregate <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> distinct signatures on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> distinct messages of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> distinct signers into a single signature reduces communication overhead and computational cost. Due to the suitability of certificateless signature (CLS) and certificateless aggregate signature (CLAS) schemes for IoT environments, similar CLS and CLAS schemes have been proposed for a long time and, despite their security proofs, they have been attacked and modified to prevent the attacks. Even now, similar design methods and similar attacks on the schemes are being repeated. In order to prevent the similar attacks on the schemes, it is necessary to analyze their causes and vulnerabilities. In this paper, we first show that recently proposed five CLS and CLAS schemes are insecure against universal forgery attacks, type I attacks, type II attacks or malicious-but-passive-KGC attacks. We discuss their security flaws, causes and countermeasures. We then present design principles to prevent various algebraic attacks including our attacks. The design principles will help in the construction of secure CLS and CLAS schemes against the previous attacks and potential attacks.

Observer Attack on Stream Ciphers

This paper proposes an application of a new observer theory for non-linear systems developed previously to solve the Cryptanalysis problem of a special class of pseudorandom generators which are commonly used in Cryptography. The Cryptanalysis problem addressed here is that of the recovery of internal state of the non-linear dynamic stream generator from the output stream. The proposed methodology is termed as observability attack. It is also shown that for a special class of generators, the computations are of complexity O(D4) in pre-computation and of O(D) for online computation, where D = σdi=0(n i) for this class of stream generators with n states and d the degree of the output function. The attack is technically applicable over general finite fields as well as most dynamic systems arising from models of stream ciphers and appropriate bounds on computation are estimated. From these complexity bounds, it follows that this attack is feasible in realistic cases and gives important estimates of time and memory resources required for Cryptanalysis of a class of stream ciphers.

Profiled Side-Channel Attack on Cryptosystems Based on the Binary Syndrome Decoding Problem

The NIST standardization process for post-quantum cryptography has been drawing the attention of researchers to the submitted candidates. One direction of research consists in implementing those candidates on embedded systems and that exposes them to physical attacks in return. The <i>Classic McEliece</i> cryptosystem, which is among the four finalists of round 3 in the Key Encapsulation Mechanism category, builds its security on the hardness of the syndrome decoding problem, which is a classic hard problem in code-based cryptography. This cryptosystem was recently targeted by a laser fault injection attack leading to message recovery. Regrettably, the attack setting is very restrictive and it does not tolerate any error in the faulty syndrome. Moreover, it depends on the very strong attacker model of laser fault injection, and does not apply to optimised implementations of the algorithm that make optimal usage of the machine words capacity. In this article, we propose a to change the angle and perform a message-recovery attack that relies on side-channel information only. We improve on the previously published work in several key aspects. First, we show that side-channel information, obtained with power consumption analysis, is sufficient to obtain an integer syndrome, as required by the attack framework. This is done by leveraging classic machine learning techniques that recover the Hamming weight information very accurately. Second, we put forward a computationally-efficient method, based on a simple dot product and information-set decoding algorithms, to recover the message from the, possibly inaccurate, recovered integer syndrome. Finally, we present a masking countermeasure against the proposed attack.

Метод оценивания квантовой устойчивости блокчейн-платформ

Abstract Purpose of work is the development of a new method for estimating the quantum resilience of modern blockchain platforms based on the effective solution of cryptanalysis problems for asymmetric encryption schemes (RSA, El-Gamal) and digital signature (DSA, ECDSA or RSA-PSS), based on computationally difficult problems of factorization and discrete logarithm. Research method is the use of quantum algorithms providing exponential gain (eg Shor’s algorithm) and quadratic gain (eg Grover’s algorithm). Due to the fact that the class of problems solved by quantum algorithms in polynomial time cannot yet be significantly expanded, more attention is paid to cryptanalysis based on the quantum Shor algorithm and other polynomial algorithms. Results of the study include a classification of well-known algorithms and software packages for cryptanalysis of asymmetric encryption schemes (RSA, El-Gamal) and digital signature (DSA, ECDSA or RSA-PSS) based on computationally difficult problems of factorization and discrete logarithm has been built. A promising method for solving problems of cryptanalysis of asymmetric encryption schemes (RSA, ElGamal) and digital signature (DSA, ECDSA or RSA-PSS) of known blockchain platforms in polynomial time in a quantum computing model is proposed. Algorithms for solving problems of quantum cryptanalysis of two-key cryptography schemes of known blockchain platforms in polynomial time are developed, taking into account the security of the discrete algorithm (DLP) and the discrete elliptic curve algorithm (ECDLP). A structural and functional diagram of the software package for quantum cryptanalysis of modern blockchain platforms “Kvant-K”, adapted to work in a hybrid computing environment of the IBM Q quantum computer (20 and 100 qubits) and the IBM BladeCenter (2022) supercomputer, has been designed. A methodology has been developed for using the “Kvant-K” software package to assess the quantum stability of blockchain platforms: InnoChain (Innopolis University), Waves Enterprise (Waves, Vostok), Hyperledger Fabric (Linux, IBM), Corda Enterprise, Bitfury Exonum, Blockchain Industrial Alliance, Exonum (Bitfury CIS), NodesPlus (b41), Masterchain (Sberbank), Microsoft Azure Blockchain, Enterprise Ethereum Alliance, etc. Practical relevance: The developed new solution for computationally difficult problems of factorization and discrete logarithm, given over finite commutative (and non-commutative) associative algebras, in a quantum model of computing in polynomial time. It is essential that the obtained scientific results formed the basis for the development of the corresponding software and hardware complex “Kvant-K”, which was tested in a hybrid computing environment (quantum computer IBM Q (20 and 100 qubits) and/or 5th generation supercomputer: IBM BladeCenter (2022), RCS based on FPGA Virtex UltraScale (2020), RFNC-VNIIEF (2022) and SKIF P-0.5 (2021). An appropriate method for estimating the quantum stability of these blockchain platforms based on the author’s models, methods and algorithms of quantum cryptanalysis has been developed and tested. Keywords: blockchain and distributed ledger technologies (DLT), SMART contracts, blockchain security threat model, quantum security threat, cryptographic attacks, quantum cryptanalysis, quantum and post-quantum cryptography, quantum algorithms Shor, Grover and Simon algorithms, quantum Fourier transform, factorization and discrete logarithm problem, post-quantum cryptography, quantum resilience of blockchain platforms.

Secure Selections on Encrypted Multi-writer Streams

Performing searches over encrypted data is a very current and active area. Several efficient solutions have been provided for the single-writer scenario in which all sensitive data originate with one party (the Data Owner ) that encrypts and uploads the data to a public repository. Subsequently, the Data Owner accesses the encrypted data through a Query Processor , which has direct access to the public encrypted repository. Motivated by the recent trend in pervasive data collection, we depart from this model and consider a multi-writer scenario in which the data originate with several and mutually untrusted parties, the Data Sources . In this new scenario, the Data Owner provides public parameters so that each Data Source can add encrypted items to the public encrypted stream; moreover, the Data Owner keeps some related secret information needed to generate tokens so that different Query Sources can decrypt different subsets of the encrypted stream, as specified by corresponding access policies. We propose security model for this problem that we call Secure Selective Stream ( SSS ) and give a secure construction for it based on hard problems in Pairing-Based Cryptography. The cryptographic core of our construction is a new primitive, Amortized Orthogonality Encryption , that is crucial for the efficiency of the proposed implementation for SSS .

A Comparative Study on Anonymizing Networks: TOR, I2P, and Riffle Networks Comparison

Background and Objectives: Among miscellaneous networks, onion-based routing network technologies such as The Onion-based Routing (ToR), Invisible Internet Project (I2P), and Riffle networks are used to communicate anonymously by different worldwide users for security, privacy, and safety requirements. Sometimes, these types of networks sacrifice anonymity for the sake of efficient communication or vice-versa. This paper surveys aforementioned networks for investigating their potential and challenges.Methods: Onion-routing networks encapsulate messages in several layers of encryption similar to layers of an onion. The anonymous communication networks are involved dining cryptographers (DC) problem so-called DC-nets, which need sending anonymous message with unconditional sender and untraceable receipt. So, DC-nets must be resistant against traffic analysis attacks although they will attenuate the network bandwidth. In this line, ToR is a free software that provides anonymous communication, I2P networks are based on hidden internet service project which uses tunnelling for anonymous communications, and Riffle networks include a small set of camouflaging servers that provide anonymity for authorized users. This paper presents a comparative study on anonymizing ToR, I2P, and Riffle networks in terms of associated prominent parameters in this vein.Results: The comparison is based on similarities, differences, and challenges in network behaviors. This comparison is beneficial for further researches and future improvements.Conclusion: The review of the current paper reveals that the Riffle networks are more resilient and have great confidentiality and integrity against other onion-based routing networks.

Quantum Key Distribution by Drone

A cryptographic communication system is secure from a practical point of view if the encryption scheme can be broken after X years, where X is determined by security needs and existing technology. Quantum cryptography does not offer a complete solution for all cryptographic problems: secure keys, encryption algorithms based on them, message authentication and finding ways to detect/prevent interception; but it can be seen as a complement to standard symmetric cryptographic systems. This paper presents the implementation of the BB84 quantum key distribution protocol on mobile systems - Amov-lab’s Z410 drone with T-engine 2216 - and tracks the error rate obtained in flight conditions.

The Ring-LWE Problem in Lattice-Based Cryptography: The Case of Twisted Embeddings.

Several works have characterized weak instances of the Ring-LWE problem by exploring vulnerabilities arising from the use of algebraic structures. Although these weak instances are not addressed by worst-case hardness theorems, enabling other ring instantiations enlarges the scope of possible applications and favors the diversification of security assumptions. In this work, we extend the Ring-LWE problem in lattice-based cryptography to include algebraic lattices, realized through twisted embeddings. We define the class of problems Twisted Ring-LWE, which replaces the canonical embedding by an extended form. By doing so, we allow the Ring-LWE problem to be used over maximal real subfields of cyclotomic number fields. We prove that Twisted Ring-LWE is secure by providing a security reduction from Ring-LWE to Twisted Ring-LWE in both search and decision forms. It is also shown that the twist factor does not affect the asymptotic approximation factors in the worst-case to average-case reductions. Thus, Twisted Ring-LWE maintains the consolidated hardness guarantee of Ring-LWE and increases the existing scope of algebraic lattices that can be considered for cryptographic applications. Additionally, we expand on the results of Ducas and Durmus (Public-Key Cryptography, 2012) on spherical Gaussian distributions to the proposed class of lattices under certain restrictions. As a result, sampling from a spherical Gaussian distribution can be done directly in the respective number field while maintaining its format and standard deviation when seen in via twisted embeddings.

The Seventh International Olympiad in Cryptography: Problems and solutions

The International Olympiad in Cryptography NSUCRYPTO is the unique Olympiad containing scientific mathematical problems for professionals, school and university students from any country. Its aim is to involve young researchers in solving curious and tough scientific problems of modern cryptography. In 2020, it was held for the seventh time. Prizes and diplomas were awarded to 84 participants in the first round and 49 teams in the second round from 32 countries. In this paper, problems and their solutions of NSUCRYPTO'2020 are presented. We consider problems related to attacks on ciphers and hash functions, protocols, permutations, primality tests, etc. We discuss several open problems on JPEG encoding, Miller -- Rabin primality test, special bases in the vector space, AES-GCM. The problem of a modified Miller -- Rabin primality test was solved during the Olympiad. The problem for finding special bases was partially solved.

Adventures in Supersingularland

Supersingular Isogeny Graphs were introduced as a source of hard problems in cryptography by Charles, Goren, and Lauter [6] for the construction of cryptographic hash functions and have been used for key exchange SIKE. The security of such systems depends on the difficulty of finding a path between two random vertices. In this article, we study several aspects of the structure of these graphs. First, we study the subgraph given by j-invariants in , using the related isogeny graph consisting of only -rational curves and isogenies. We prove theorems on how the connected components thereof attach, stack, and fold when mapped into the full graph. The -rational vertices are fixed by the Frobenius involution on the graph, and we call the induced graph the spine. Finding paths to the spine is relevant in cryptanalysis. Second, we present numerous computational experiments and heuristics relating to the position of the spine within the whole graph. These include studying the distance of random vertices to the spine, estimates of the diameter of the graph, how often paths are preserved under the Frobenius involution, and what proportion of vertices are conjugate. We compare some of the heuristics with known results on other Ramanujan graphs.

Image Security using Steganography and Cryptography

Cryptography and Steganography could be used to provide data security, each of them has a problem. Cryptography problem is that, the cipher text looks meaningless, so the attacker will interrupt the transmission or make more careful checks on the data from the sender to the receiver. Steganography problem is that once the presence of hidden information is revealed or even suspected, the message is become known . According to my proposed work in which both steganography and cryptography are combine and give good security for data. Firstly, the encrypted images has been hidden using image steganography method. Secondly, the Hash function algorithm has been modified and used to encrypt the stego image by using 128 digit hexa-key. Therefore, two levels of security have been provided using the proposed technique. In addition, the proposed technique provides high embedding capacity and better quality stego images.

Logic program invertibility in cryptography problems

This work contains an analysis of problems those occur when the logic programs are used for cryptography problems. We explore the following problems: whether a logic program is invertible; whether one program is an inverse of the other. It was proved coNP-completeness for both problems. The size of logic programs also considered. We have found an instance of a program of linear length such that the length of the inverse program is exponential.

Some results of development of cryptographic transformations schemes using non-abelian groups

Implementation of a successful attack on classical public key cryptosystems becomes more and more real with the advent of practical results in the implementation of Shor's and Grover's algorithms on quantum computers. Modern results in tackling the problem of building a quantum computer of sufficiently power justify the need to revise the existing approaches and determine the most effective in terms of solving problems of post-quantum cryptography. One of these promising research priorities is the study of the cryptosystems based on non-abelian groups.&#x0D; The problems of conjugacy search, membership search, and others are difficult to solve in the theory of non-abelian groups and are the basis for building provably secure public key cryptosystems. This paper gives an overview of the most frequently discussed algorithms using non-abelian groups: matrix groups braid groups, semi direct products, and algebraic erasers (AE). The analysis of the construction of encryption and decryption schemes, key establishment mechanisms is given. Many non-abelian group-based key establishment protocols are associated with the Diffie – Hellman (DH) protocol. The paper analyzes the properties of non-abelian group public key encryption schemes. Various cryptographic primitives using non-commutative groups as a basis for post-quantum schemes are considered.

Post-Quantum Cryptosystems for Internet-of-Things: A Survey on Lattice-Based Algorithms

The latest quantum computers have the ability to solve incredibly complex classical cryptography equations particularly to decode the secret encrypted keys and making the network vulnerable to hacking. They can solve complex mathematical problems almost instantaneously compared to the billions of years of computation needed by traditional computing machines. Researchers advocate the development of novel strategies to include data encryption in the post-quantum era. Lattices have been widely used in cryptography, somewhat peculiarly, and these algorithms have been used in both; (a) cryptoanalysis by using lattice approximation to break cryptosystems; and (b) cryptography by using computationally hard lattice problems (non-deterministic polynomial time hardness) to construct stable cryptographic functions. Most of the dominant features of lattice-based cryptography (LBC), which holds it ahead in the post-quantum league, include resistance to quantum attack vectors, high concurrent performance, parallelism, security under worst-case intractability assumptions, and solutions to long-standing open problems in cryptography. While these methods offer possible security for classical cryptosytems in theory and experimentation, their implementation in energy-restricted Internet-of-Things (IoT) devices requires careful study of regular lattice-based implantation and its simplification in lightweight lattice-based cryptography (LW-LBC). This streamlined post-quantum algorithm is ideal for levelled IoT device security. The key aim of this survey was to provide the scientific community with comprehensive information on elementary mathematical facts, as well as to address real-time implementation, hardware architecture, open problems, attack vectors, and the significance for the IoT networks.

Additional Security using Three-Pass Protocol and Pohlig-Hellman

Data and information protection is usually done by encrypting sensitive data and information using cipher keys or symmetric algorithms. This includes using what is known as “cipher keys,” which are used in systems that require two parts, a sender’s and receiver’s part, which is a special system that needs to be assembled, and a location where data is sent to or stored. The Three-Pass Protocol and Pohlig Hellman Algorithm solves a key distribution problem in symmetric and asymmetric cryptography, allowing senders and receivers to process encryption and decryption due to lack of key distribution processes.