Search

Blockchain technology has evolved from its origins in cryptocurrencies to become a fundamental component of secure digital interactions across diverse sectors, including healthcare, finance, and public administration. This article delves into the theoretical and practical applications of cryptography within blockchain networks, emphasizing key cryptographic functions, algorithms, and protocols such as RSA, elliptic curve cryptography (ECC), and SHA-256. It scrutinizes the use of digital signatures for transaction verification and the crucial role of hash functions in ensuring data integrity. Additionally, the article presents practical examples of symmetric and asymmetric encryption methods, underscoring their significance in maintaining privacy and security. The study also highlights the emerging challenges posed by quantum computing and explores ongoing research in post-quantum cryptography. Furthermore, it provides insights into the advancements in cryptographic techniques essential for the robustness of decentralized networks. By linking theoretical frameworks with practical implementations, this article aims to offer a comprehensive understanding of the cryptographic security measures pivotal for the future of blockchain technology. [ABSTRACT FROM AUTHOR]

This article presents a security formal analysis of the hybrid post-quantum Transport Layer Security (TLS) protocol, a quantum-resistant version of the TLS protocol proposed by Amazon Web Services as a precaution in dealing with future attacks from quantum computers. In addition to a classical key exchange algorithm, the proposed protocol uses a post-quantum key encapsulation mechanism, which is believed invulnerable under quantum computers, so the protocol's key negotiation is called the hybrid key exchange scheme. One of our assumptions about the intruder's capabilities is that the intruder is able to break the security of the classical key exchange algorithm by utilizing the power of large quantum computers. For the formal analysis, we use Maude-NPA and a parallel version of Maude-NPA (called Par-Maude-NPA) to conduct experiments. The security properties under analysis are (1) the secrecy property of the shared secret key established between two honest principals with the classical key exchange algorithm, (2) a similar secrecy property but with the post-quantum key encapsulation mechanism, and (3) the authentication property. Given the time limit T D 1,722 h (72 days), Par-Maude-NPA found a counterexample of (1) at depth 12 in T, while Maude-NPA did not find it in T. At the same time T, Par-Maude-NPA did not find any counterexamples of (2) and (3) up to depths 12 and 18, respectively, and neither did Maude-NPA. Therefore, the protocol does not enjoy (1), while it enjoys (2) and (3) up to depths 12 and 18, respectively. Subsequently, the secrecy property of the master secret holds for the protocol up to depth 12. [ABSTRACT FROM AUTHOR]

In the setting of secure multiparty computation, a set of parties wish to carry out a joint computation of their inputs while keeping them private. In this paper, we describe new information-theoretic protocols for secure three-party computation with an honest majority. Our protocols compute Boolean circuits with minimal computation and communication. We start with a protocol, based on replicated secret sharing, which is secure in the presence of semi-honest adversaries in which the parties communicate only a single bit per AND gate. Then, we show how to modify it to be secure in the presence of malicious adversaries. Our malicious protocol follows the paradigm of first constructing Beaver multiplication triples and then using them to verify that circuit gates are correctly computed. As in previous work (e.g., the so-called TinyOT and SPDZ protocols), we rely on the cut-and-choose paradigm to verify that triples are correctly constructed. We are able to utilize the fact that at most one of three parties is corrupted in order to construct an extremely simple and efficient method of constructing such triples. Then, we provide general techniques for improving efficiency of cut-and-choose protocols on multiplication triples and utilize them to further improve the protocol. The resulting protocol for malicious adversaries has bandwidth of only 7 bits per AND gate per party, when amortizing over 1 million gates and with statistical error 2 - 40 . An implementation of our protocol achieves a throughput of over 7 billion AND gates per second with the semi-honest protocol, and over 1 billion AND gates per second with the malicious protocol (using the above parameters). Our results demonstrate that high-throughput secure computation is possible. [ABSTRACT FROM AUTHOR]

The rapid deployment of software, such as online banking, stock trading and corporate remote access, has seen tremendous growth in the amount of sensitive data shared over the internet in recent years. In addition, these internet hosts are predominantly battery-powered, portable, handheld devices with stringent memory, CPU, latency and bandwidth limitations. This paper discusses the design of modern elliptic curve cryptographic (ECC) high-speed architecture using field-programmable gate array (FPGA) technique for elliptic curve based multi level key exchange and encryption mechanism (ECM-KEEM) protocol. Different safety levels are applied to the data path to investigate the outcome of the results and to find maximum protection for the higher bits of data. Three complex security algorithms are used to upgrade the mathematical hardness of the designed system by incorporating the novel functions for secret key exchange. The field arithmetic in the prime field curve secp256k1 used in the designed architecture achieves a time period of 0.3 microseconds and 0.8 microseconds by conventional multipliers and Vedic multipliers respectively on various Xilinx Virtex-6 FPGA platform. Alongside the same design is implemented and analyzed with Virtex-7 and Kintex-7 platforms for the better performance to verify the improved implementation efficiency with Vedic multiplier based design. The latest trends in the e-gadgets needs an effective, scalable security mechanisms and protocols with efficient hardware architecture are clearly needed that function well in both wired and wireless environments. [ABSTRACT FROM AUTHOR]

Nowadays, technological advances provide people with more facilities and luxuries in life. Medicine is no exception; for example, different wireless sensors can be used to monitor patients' state of health. These sensors are used in the so-called Wireless Body Area Networks (WBAN), to improve the efficiency of doctor-patient activities at any time, in any body area, and anywhere. However, health data contains sensitive information that becomes a critical issue requiring special attention when transmitted within a WBAN. In other words, WBAN must be protected from malicious devices that intercept, alter or access without authorization or even deny the health information being transmitted. In this article, we present the design of a new cryptographic protocol that guarantees three security services, authentication, confidentiality, and integrity by securing sensitive information communication through a WBAN. We also consider a keyless sensors authentication method to distinguish whether or not the devices are placed on the same individual's body. A formal analysis of the protocol is carried out using cryptographic protocol verification tools to guarantee its correct construction and that it provides appropriate security. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) generates a significant volume of geo-tagged images via surveillance sensors in edge–cloud computing environments. Image search is essential to facilitate information sharing, data analysis, and strategic decision-making. However, outsourced images are typically encrypted for privacy protection, posing a challenge in simultaneously searching for visual and geographical relevance on encrypted images. To address this, this paper proposes an edge intelligence empowered privacy-preserving top- k geo-tagged image search scheme for IoT in edge–cloud computing. The scheme presents a novel single-to-multi searchable encryption method for geo-tagged images that enables multiple users to perform secure nearest neighbor queries on a data source. Additionally, an extended anchor-based position determination method and an inner product-based distance calculation method are designed to enable geo-tagged image similarity calculation on ciphertext. Finally, a secure pruning method is introduced to improve query performance. Experiments are conducted to verify the performance of the scheme in terms of high efficiency and accuracy of the search. • Single-to-multi searchable encryption model on geo-tagged images. • Secure nearest neighbor queries on geo-tagged images. • Secure pruning based on the extended locality-sensitive hashing. • Distance calculation from an encrypted data point to an encrypted space. • Extended anchor-based position determination. [ABSTRACT FROM AUTHOR]

Algorithms for exchanging messages between subscribers are proposed based on the properties of finite associative-commutative rings with unity and Diophantine equations over such rings. Algorithms for constructing finite rings whose additive groups are full-cycle, and algorithms for constructing isomorphisms between a ring of kth order whose additive group is full-cycle and the residue ring Zk modulo k are presented. [ABSTRACT FROM AUTHOR]

This work presents a security analysis of the QUIC handshake protocol based on symbolic model checking. As a newly proposed secure transport protocol, the purpose of QUIC is to improve the transport performance of HTTPS traffic and enable rapid deployment and evolution of transport mechanisms. QUIC is currently in the IETF standardization process and will potentially carry a significant portion of Internet traffic in the emerging future. For a better understanding of the essential security properties, we have developed a formal model of the QUIC handshake protocol and perform a comprehensive formal security analysis by using two state-of-the-art model checking tools for cryptographic protocols, i.e., ProVeirf and Verifpal. Our analysis shows that ProVerif is generally more powerful than Verifpal in terms of verifying authentication properties. Moreover, both tools produce a counterexample to some security properties, which reveal a design flaw in the current protocol specification. Last but not least, we analyze the root causes of this counterexample and suggest a possible fix.

Nowadays, technological advances provide people with more facilities and luxuries in life. Medicine is no exception; for example, different wireless sensors can be used to monitor patients’ state of health. These sensors are used in the so-called Wireless Body Area Networks (WBAN), to improve the efficiency of doctor-patient activities at any time, in any body area, and anywhere. However, health data contains sensitive information that becomes a critical issue requiring special attention when transmitted within a WBAN. In other words, WBAN must be protected from malicious devices that intercept, alter or access without authorization or even deny the health information being transmitted. In this article, we present the design of a new cryptographic protocol that guarantees three security services, authentication, confidentiality, and integrity by securing sensitive information communication through a WBAN. We also consider a keyless sensors authentication method to distinguish whether or not the devices are placed on the same individual’s body. A formal analysis of the protocol is carried out using cryptographic protocol verification tools to guarantee its correct construction and that it provides appropriate security.

The security of the cryptographic protocols has always been important to ensure proper implementation of a protocol. To assure protocol security, a number of works for analysis and verification of cryptographic protocols have emerged in the literature. In this paper, with dynamic epistemic logic, we propose a model approach to analyze a cryptographic protocol. In order to capture the security properties of the protocol, we present the update of the epistemic states based on the epistemic actions. The epistemic actions lead to changes in the knowledge set of the agents participating in the protocol. We model this execution process of the specific example of the cryptographic protocol using the Kripke models and the transition between states. The result of analysis demonstrates that this cryptographic protocol conforms to the security requirements.

Copyright of Cybernetics & Systems Analysis / Kibernetiki i Sistemnyj Analiz is the property of V.M. Glushkov Institute of Cybernetics of NAS of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ensuring the security and privacy of vehicle is one of the critical requirements for the safety and reliability of vehicular ad hoc networks. A variety of (conditional) anonymous authentication schemes, including group/ring signatures, pseudo-identity-based and PKI-based approaches, have been proposed to achieve highly effective privacy-preserving authentications. A recent effort, i.e., randomized authentication, leverages homomorphic encryption for vehicles to self-generate authenticated identities to achieve full anonymity. Notwithstanding a very attractive feature to prevent single-party traceability, randomized authentication faces a great challenge on the centralized data updating and the frequent clock synchronizations. It also fails to meet the necessity of non-repudiation. In this paper, we present a rigorous decentralized randomized authentication framework with conditional privacy preservation. We use homomorphic encryption and a one-way hash chain for a vehicle to self-generate randomized pseudoidentities. We deploy the pseudonym validation mechanism over the roadside units in order to support decentralized mutual identity authentication and ownership validation of vehicles in a loosely coupled or a compound manner. Our framework can provide rigorous Level 3 privacy and traceability of vehicles. We also provide a security condition on valid random values to ensure the uniqueness of pseudonym and non-repudiation of vehicles. The performance evaluation shows that our framework is generally more efficient on infrastructures in terms of computational and communication overheads than the state-of-the-art randomized authentications.

The security of cryptographic protocols has always been an important issue. Although there are various verification schemes of protocols in the literature, efficiently and accurately verifying cryptographic protocols is still a challenging research task. In this work, we develop a formal method based on dynamic epistemic logic to analyze and describe cryptographic protocols. In particular, we adopt the action model to depict the execution process of the protocol. To verify the security, the intruder's actions are analyzed. We model exactly the protocol applying our formal language and give the verification models according to the security requirements of this cryptographic protocol. With analysis and proof on a selected example, we show the usefulness of our method. The result indicates that the selected protocol meets the security requirements. [ABSTRACT FROM AUTHOR]

We propose the first auctioneer-free sealed-bid auction protocol with a linear computation and communication complexity $O(c)$ , $c$ being the bit length of the bid price. Our protocol, called Self-Enforcing Auction Lot (SEAL), operates in a decentralized setting, where bidders jointly compute the maximum bid while preserving the privacy of losing bids. In our protocol, we do not require any secret channels between participants. All operations are publicly verifiable; everyone including third-party observers is able to verify the integrity of the auction outcome. Upon learning the highest bid, the winner comes forward with a proof to prove that she is the real winner. Based on the proof, everyone is able to check if there is only one winner or there is a tie. While our main protocol works with the first-price sealed-bid, it can be easily extended to support the second-price sealed-bid (also known as the Vickrey auction), revealing only the winner and the second highest bid, while keeping the highest bid and all other bids secret. To the best of our knowledge, this work establishes to date the best computation and communication complexity for sealed-bid auction schemes without involving any auctioneer. [ABSTRACT FROM AUTHOR]

There is a major interest in designing RFID schemes based on symmetric-key cryptography and ensuring efficient tag identification. These requirements taken together often lead to a decrease in the degree of privacy provided by the scheme. This issue, as we know, has been treated in an ad-hoc manner so far. In this paper, we introduce the class of stateful RFID schemes with constant tag identifiers, that ensure tag identification in no more than logarithmic time. In order to study their privacy, we propose an appropriate general model obtained by constraining Vaudenay’s model. We then propose two symmetric-key cryptography based RFID schemes in this class that achieve weak and destructive privacy, respectively, in addition to mutual authentication. We also discuss on the degree of privacy provided by other schemes proposed in the literature, that fall in this class. [ABSTRACT FROM AUTHOR]

In this most revolutionized world, the social network plays a vital role in each and everyone's life. Social networking is a pervasive communication platform where the users can search whole over the world via the Internet. Users have similar interest to connect and interact with one another and to share their private and personal interest. In this paper, we examine privacy concern for the social networking users by distributed clustering method. In the proposed scheme, to speed-up, the Kernel k-means algorithm, a prototype based hybrid kernel k-means algorithm is involved in distributing the users into the cluster. Since we are using a large data set, we use a hybrid approach to speed-up the kernel k-means clustering (HSKK). The clustering process used here is to partition a similar set of objects in a dataset. Additionally, in the clustering process, a cryptographic protocol such as homomorphic encryption is involved in every dataset to achieve the goal to protect the private data. To prove the efficiency of the proposed approach, the experiment is done on Movie lens dataset. The experimental study of HSKK shows that the proposed method can significantly reduce the computation time and the private data of users is hidden from the service provider. [ABSTRACT FROM AUTHOR]

Biometrics security is a dynamic research area spurred by the need to protect personal traits from threats like theft, non‐authorised distribution, reuse and so on. A widely investigated solution to such threats consists of processing the biometric signals under encryption, in order to avoid any leakage of information towards non‐authorised parties. In this study, the authors propose to leverage on the superior performance of multimodal biometric recognition to improve the efficiency of a biometric‐based authentication protocol operating on encrypted data under the malicious security model. In the proposed protocol, authentication relies on both facial and iris biometrics, whose representation accuracy is specifically tailored to the trade‐off between recognition accuracy and efficiency. From a cryptographic point of view, the protocol relies on Damgård et al. SPDZ. Experimental results show that the multimodal protocol is faster than corresponding unimodal protocols achieving the same accuracy. [ABSTRACT FROM AUTHOR]