Blockchain Papers

Basudeb Bera, Anusha Vangala, Ashok Kumar Das, Pascal Lorenz · 5 authors

No abstract is available for this record.

Vankamamidi S. Naresh, V. V. L. Divakar Allavarpu, Sivaranjani Reddi, Pilla Sita Rama Murty · 6 authors

Summary Group key management with privacy preserving and trust still remains a precarious and stimulating issue for securing multicast communications in an energy embarrassed large wireless ad‐hoc networks (WANETs). To address this, few researchers with the adaption of blockchain technology and practical usage of a privacy‐preserving smart contract as group controller made these group key agreements adaptable to WANET. However, proportionate to the increase in the size of the group, the processing load on the smart contract is also increasing, which made the capability of the smart contract could not work beyond a certain group size. Contemporary blockchain schemes suffer from various inherent shortcomings in their latency, scalability, and processing throughput. So, in this direction, we adopted blockchain sharding smart contract‐centric processing for making the key agreement adaptable to large WANETs. In this technique, we divide the large network into r sharded subnetworks with G 1 , G 2 , G 3 , …, G r as smart contract instances generated by group controller G , which acts as subgroup controllers to their respective shards using blockchain sharding technique. This protocol is shown secure under the assumptions elliptic curve decision Diffie–Hellman and group‐elliptic curve Diffie–Hellman. The performance analysis demonstrates that the proposed protocol is highly proficient than examined protocols for secure communication in large WANETs.

А. В. Анисимов, Andrey Novokshonov

We describe a fast three-round mutual authentication protocol for parties A and B belonging to the same coalition group. Parties A and B keep their own independent long-term private keys that are used in the process of authentication and can be used for other purposes. The scheme assumes an initial setup with a trusted third party T. This party initiates another secret information that includes factors of a large RSA modulus. For authentication, both parties must demonstrate each other the knowledge of their private keys without revealing them and the ability to factorize a large RSA modulus. Thus, the protocol based on the suggested scheme provides reciprocal authentication. The scheme possesses all desirable properties of an interactive proof, i.e., completeness, soundness, and zero-knowledge. The security of the protocol relies on assumptions of difficulty of the RSA factorization and existence of a cryptographic hash function.

Sofia Terzi, Charalampos Savvaidis, Athanasios Sersemis, Konstantinos Votis · 5 authors

With smart vehicles interconnected with multiple systems and other entities, whether they are people or IoT devices, the importance of a digital identity for them has emerged. We present in this paper how a Self-Sovereign Identities combined with blockchain can provide a solution to this end, in order to decentralize the identity management and provide them with capabilities to identify the other entities they interact with. Such entities can be the owners of the vehicles, other drivers and workshops that act as service providers. Two use cases are examined along with the interactions between the participants, to demonstrate how a decentralized identity management solution can take care of the necessary authentication and authorization processes. Finally, we test the system and provide the measurements to prove its feasibility in real-life deployments.

Lyuye Zhang, Maode Ma, Yue Qiu

No abstract is available for this record.

Durbadal Chattaraj, Basudeb Bera, Ashok Kumar Das, Sourav Saha · 6 authors

In the Internet of Vehicles (IoV), numerous potential applications have come up with the use of the Internet of Things (IoT)-empowered smart devices. In IoV, vehicles, roads, street signs and traffic lights can accordingly adjust to changing conditions in order to assist drivers, and also to improve safety, ease congestion and pollution reduction. Since various entities in an IoV environment make communications over public channels, there are potential security threats. To deal with such serious threats, we design a new blockchain-assisted certificateless key agreement protocol for IoV in smart transportation context, called Block-CLAP. In Block-CLAP, through authentication key management, traffic-centric data reach to a cluster head (CH) and then to its nearby road-side unit (RSU) securely using the established secret keys. A cloud server (CS) then securely collects the information from its attached RSUs and create the transactions. Later, the transactions are formed into blocks by the CS in a Peer-to-Peer (P2P) cloud servers network, and the blocks are verified and added through voting-based consensus algorithm in the blockchain. The detailed security analysis through formal, informal and formal security verification, and comparative study show that Block-CLAP provides superior security and has low communication and computational overheads as compared with other existing competing authentication schemes in the IoV environment. Finally, the blockchain-based implementation of Block-CLAP has been performed to measure computational time needed for a varied number of transactions per block and also for a varied number of blocks mined in the blockchain.

Josep Lluís Ferrer Gomila, M. Francisca Hinarejos

Fair digital signature of contracts and agreements is an essential process in any electronic commerce scenario, and therefore also in data marketplaces, where the relationships and agreements among the different parties (consumers and providers) are more dynamic. In multi-party contract signing, N parties wish to sign a contract in a such a way that either all signatories obtain evidence of the signing or none obtains conflicting evidence regarding the honest signatories; the exchange must be fair. In this paper, we propose a blockchain-based multi-party contract signing protocol. This solution does not require the existence or potential intervention of a trusted third party (TTP), thus avoiding the difficulty of N signatories agreeing upon a TTP. In addition, this proposal meets the necessary requirements: fairness, timeliness, non-repudiation of origin, and non-repudiation of receipt. Furthermore, confidentiality can be easily achieved. To minimize costs associated with the use of blockchain, it should be invoked in the case of exception (analogous to optimistic solutions with a TTP) and by only one of the N signatories. However, when the use of blockchain is required, we show that its cost is within perfectly manageable margins.

Justin Holmgren, Alex Lombardi, Ron D. Rothblum

In a seminal work, Goldreich, Micali and Wigderson (CRYPTO ’86) demonstrated the wide applicability of zero-knowledge proofs by constructing such a proof system for the NP-complete problem of graph 3-coloring. A long-standing open question has been whether parallel repetition of their protocol preserves zero knowledge. In this work, we answer this question in the negative, assuming a standard cryptographic assumption (i.e., the hardness of learning with errors (LWE)).

Fengye Yu, Maode Ma, Xiaohong Li

The Fifth Generation (5G) wireless network needs many base stations to provide ultra-high throughput. Thus, the vehicles in Vehicles to Infrastructure (V2I) communication over a 5G wireless network have to perform more frequent mutual authentications than before, which will greatly reduce the efficiency of the entire network. To address this issue, in this paper, we propose a novel handover authentication protocol that incorporates the blockchain based smart contracts to remove redundancy in the traditional handover authentication. Our proposed scheme can achieve the mutual authentication and key agreement between vehicles and base stations in 5G wireless networks, while it can largely reduce the cost for the handover authentication at the same time. The formal verification by Scyther indicates that the proposed protocol can resist various malicious attacks. In addition, the performance evaluation results show that the delay incurred by handover authentication can be significantly reduced indicating that the proposed protocol is feasible and holds potential to be used in the deployment of 5G wireless networks.

Nikolaj Sidorenco, Sabine Oechsner, Bas Spitters

Zero-knowledge proofs allow a prover to convince a verifier of the veracity of a statement without revealing any other information. An interesting class of zero-knowledge protocols are those following the MPC-in-the-head paradigm (Ishai et al., STOC '07) which use secure multiparty computation (MPC) protocols as the basis. Efficient instances of this paradigm have emerged as an active research topic in the last years, starting with ZKBoo (Giacomelli et al., USENIX '16). Zero-knowledge protocols are a vital building block in the design of privacy-preserving technologies as well as cryptographic primitives like digital signature schemes that provide post-quantum security. This work investigates the security of zero-knowledge protocols following the MPC-in-the-head paradigm. We provide the first machine-checked security proof of such a protocol on the example of ZKBoo. Our proofs are checked in the EasyCrypt proof assistant. To enable a modular security proof, we develop a new security notion for the MPC protocols used in MPC-in-the-head zero-knowledge protocols. This allows us to recast existing security proofs in a black-box fashion which we believe to be of independent interest.

Weizheng Wang, Hao Xu, Mamoun Alazab, Thippa Reddy Gadekallu · 6 authors

Nowadays, the Industrial Internet of Things (IIoT) has remarkably transformed our personal lifestyles and society operations into a novel digital mode, which brings tremendous associations with all walks of life, such as intelligent logistics, smart grid, and smart city. Moreover, with the rapid increase of IIoT devices, a large amount of data is swapped between heterogeneous sensors and devices every moment. This trend increases the risk of eavesdropping and hijacking attacks in communication channels, so maintaining data privacy and security becomes two notable concerns at present. Recently, based on the mechanism of the Schnorr signature, a more secure and lightweight certificateless signature (CLS) protocol is popular for the resource-constrained IIoT protocol design. Nevertheless, we found most of the existing CLS schemes are susceptible to several common security weaknesses such as man-in-the-middle attacks, key generation center compromised attacks, and distributed denial of service attacks. To tackle the challenges mentioned previously, in this article, we propose a novel pairing-free certificateless scheme that utilizes the state-of-the-art blockchain technique and smart contract to construct a novel reliable and efficient CLS scheme. Then, we simulate the Type-I and Type-II adversaries to verify the trustworthiness of our scheme. Security analysis as well as performance evaluation outcomes prove that our design can hold more reliable security assurance with less computation cost (i.e., reduced by around 40.0% at most) and communication cost (i.e., reduced by around 94.7% at most) than other related schemes.

Chin‐Ling Chen, Zi-Yi Lim, Hsien‐Chou Liao, Yong‐Yuan Deng · 5 authors

Tobacco products are an addictive commodity. According to the World Health Organization’s (WHO) latest statistics data, tobacco kills more than eight million people each year. In 2003, the WHO proposed the Framework Convention on Tobacco Control (FCTC) to provide an effective framework for the control of tobacco products to governments around the world. In the field of tobacco products, the hardest problem is how to prevent counterfeit tobacco products and smuggling. To solve the problems, we proposed a blockchain-based traceable and verifiable logistics system for tobacco products with global positioning system (GPS) and radio-frequency identification (RFID) Technologies. In this research, we provide an overview of system architecture, and also define the protocol and the smart contract in every phase that stores data into the blockchain center. We realized a decentralized database and authentication system that uses blockchain and smart contract technology; every protocol in every phase was designed to achieve the integrity of data and non-repudiation of message. Every tobacco product’s shipping record will be completed by scanning the RFID tag and retrieving the GPS with a mobile reader, where the record will be updated and validated in the blockchain center. In the end, the security and costs of the system were analyzed, and a comparison was made with the EU’s (European Commission) method. Our system is more flexible for transportation, more secure in the communication protocol, and more difficult to tamper and forge data. In general, the proposed scheme solved the problem of tobacco products counterfeiting and tracking issues.

Jianfeng Guan, Yinan Wu, Su Yao, Tianhong Zhang · 6 authors

No abstract is available for this record.

Muhammad Usman Aftab, Mehdi Hussain, Anders Lindgren, Abdul Ghafoor

To ensure traffic safety and proper operation of vehicular networks, safety messages or beacons are periodically broadcasted in Vehicular Adhoc Networks (VANETs) to neighboring nodes and road side units (RSU). Thus, authenticity and integrity of received messages along with the trust in source nodes is crucial and highly required in applications where a failure can result in life-threatening situations. Several digital signature based approaches have been described in literature to achieve the authenticity of these messages. In these schemes, scenarios having high level of vehicle density are handled by RSU where aggregated signature verification is done. However, most of these schemes are centralized and PKI based where our goal is to develop a decentralized dynamic system. Along with authenticity and integrity, trust management plays an important role in VANETs which enables ways for secure and verified communication. A number of trust management models have been proposed but it is still an ongoing matter of interest, similarly authentication which is a vital security service to have during communication is not mostly present in the literature work related to trust management systems. This paper proposes a secure and publicly verifiable communication scheme for VANET which achieves source authentication, message authentication, non repudiation, integrity and public verifiability. All of these are achieved through digital signatures, Hash Message Authentication Code (HMAC) technique and logging mechanism which is aided by blockchain technology.

Miqi Wu, Lin You, Gengran Hu, Liang Li · 5 authors

In a multiserver architecture, authentication schemes play an important role in the secure communication of the system. In many multiserver authentication schemes, the security of the mutual authentications among the participants is based on the security of the registration center’s private key. This centralized architecture can create security risks due to the leakage of the registration center’s private key. Blockchain technology, with its decentralized, tamper-proof, and distributed features, can provide a new solution for multiserver authentication schemes. In a lot of multiserver authentication schemes, users’ permission is generally controlled by the registration center (RC), but these permission control methods cannot be applied in the decentralized blockchain system. In this paper, a blockchain-based authentication scheme for multiserver architecture is proposed. Our scheme provides a hierarchical authentication method to solve the problems of user permission control and user revocation caused by no registration center. The security of our scheme is formally proved under the random oracle model. According to our analysis, our scheme is resistant to attacks such as impersonation attacks and man-in-the-middle attacks. In addition, our performance analysis shows that the proposed scheme has less computation overhead.

Youssef Inedjaren

Contribution au système de transport intelligent : sécurité des communications dans les réseaux Ad hoc véhiculaires Les systèmes de transport intelligents (ITS) sont un organe vital de l'évolution du secteur du transport routier et constituent l'une des principales étapes du mouvement vers l'automatisation des véhicules. Ces systèmes utilisent des technologies permettant aux véhicules de communiquer entre eux ou avec l'infrastructure routière. En augmentant la qualité et la fiabilité des informations, les STI peuvent améliorer la sécurité routière et l'efficacité du trafic, à condition que la cybersécurité et la protection des données soient assurées.Les réseaux ad hoc de véhicules (VANET) sont une projection des ITS et sont devenus un domaine de recherche important ces dernières années. Étant de nature ad hoc et ayant une mobilité élevée comme caractéristique principale, les VANET impliquent une topologie très dynamique, ce qui signifie que la plupart des protocoles de routage dédiés aux réseaux mobiles ad hoc (MANET) nécessitent des changements remarquables pour être adéquats pour les VANET.L'objectif principal de cette thèse est d'améliorer les performances des entités physiques et des communications au sein d'un ITS en termes de sécurité. Nous nous concentrons sur la fiabilité, la connectivité et l'attaque du trou noir. Nous étudions et proposons des solutions techniques à partir de la couche réseau qui jouent un rôle fondamental dans l'atténuation des défis créés par la nature de l'environnement véhiculaire.Principalement, nos contributions sont de trois ordres. Premièrement, nous considérons les efforts visant à améliorer la fiabilité des communications dans les réseaux de véhicules. Ces efforts sont représentés par des protocoles proposés visant à assurer la livraison des messages au (x) destinataire (s). En nous concentrant sur les applications de sécurité, nous nous concentrons sur l'architecture de communication ETSI ITS, en appliquant la méthodologie Threat Vulnerability Risk Assessment (TVRA). Les résultats de notre analyse sont une liste de vulnérabilités avec leur niveau de risque de gravité. Deuxièmement, nous proposons le protocole FT-OLSR (Fuzzy Trust Optimized Link State Routing), qui est une nouvelle extension de sécurité du protocole OLSR existant. FT-OLSR est basé sur l'échange de messages de contrôle avec des voisins à un bond pour permettre à chaque véhicule de calculer le niveau de confiance de ses voisins en utilisant la logique floue. Enfin, nous proposons un système de gestion de la confiance décentralisé basé sur la blockchain. Ce système est basé sur le protocole FT-OLSR, qui utilise les messages de routage échangés (HELLO, TC) dans VANET, pour calculer les valeurs de confiance, puis détecter les véhicules du trou noir. Dans le schéma proposé, une fois que l'attaquant est identifié, il est isolé de la communication en partageant ces informations en toute sécurité sur le réseau à l'aide de la blockchain. En raison des ressources limitées des VANET, le modèle Proof-of-Trust (PoT) est inséré dans le FT-OLSR, au lieu d'utiliser Proof-of-Work ou Proof-of-Stake, dans lequel l'enjeu correspond à la valeur de confiance de chaque nœud mobile. L'algorithme de consensus PoT est utilisé pour élire les validateurs. Une fois qu'un attaquant est détecté, le validateur confirme l'intégrité du rapport et crée un bloc contenant les informations des attaquants. Le bloc est diffusé sur le réseau et ajouté à la blockchain locale de chaque véhicule. Par conséquent, si le même attaquant tente de communiquer à n'importe quel endroit du réseau, une seule recherche de la blockchain peut isoler l'attaquant.

Adrián Silveira, Gustavo Betarte, Maximiliano Cristiá, Carlos Luna

MimbleWimble (MW) is a privacy-oriented cryptocurrency technology which provides security and scalability properties that distinguish it from other protocols of its kind. We present and discuss those properties and outline the basis of a model-driven verification approach to address the certification of the correctness of the protocol implementations. In particular, we propose an idealized model that is key in the described verification process, and identify and precisely state sufficient conditions for our model to ensure the verification of relevant security properties of MW. Since MW is built on top of a consensus protocol, we develop a Z specification of one such protocol and present an excerpt of the $\{log\}$ prototype generated from the Z specification. This $\{log\}$ prototype can be used as an executable model where simulations can be run. This allows us to analyze the behavior of the protocol without having to implement it in a low level programming language. Finally, we analyze the Grin and Beam implementations of MW in their current state of development.

Seyed Farhad Aghili, Hamid Mala, Christian Schindelhauer, Mohammad Shojafar · 5 authors

No abstract is available for this record.

Guanjie Cheng, Yan Chen, Shuiguang Deng, Honghao Gao · 5 authors

With the ever-increasing requirements of delay-sensitive and mission-critical applications, it becomes a popular research trend to incorporate edge computing in the Internet of Things (IoT) to mitigate the pressure of traditional cloud-based IoT architecture. Edge computing delivers real-time computations and communications for IoT devices by leveraging edge servers deployed close to users, which creates a collaborative edge computing (CEC) paradigm. The capacity of edge servers is beneficial but risky, as vulnerable servers can be exploited to conduct surveillance or perform other nefarious activities. Besides, fake IoT devices would bring security threats and compromise the IoT system. This highlights the necessity of designing a secure and efficient mutual authentication scheme for CEC. In this direction, related works have proposed various authentication mechanisms, but most of them are found unfit due to the absence of decentralization, anonymity, and mobility. Motivated by this fact, we propose a blockchain-based mutual authentication scheme that bridges these gaps. Specifically, blockchain, certificateless cryptography, elliptic curve cryptography, and pseudonym-based cryptography are integrated into our scheme to provide mutual authentication between edge servers and IoT devices. Except for static conditions, both intraedge and interedge authentication are considered. Besides, we elaborate on the key generation procedures and design a session key negotiation mechanism. Extensive experiments and security analyses have been conducted to show the feasibility of the proposed scheme.

Bernhard Schachenhofer

Mit Bitcoin wurde 2008 die erste Kryptowährung veröffentlicht. Mit ihr können Zahlungen getätigt werden, ohne einer zentralen Stelle wie einer Bank vertrauen zu müssen. Dies wird durch einen innovativen Konsensus-Mechanismus ermöglicht, der unter der Bezeichnung Proof-of-Work bekannt ist. Bitcoin ist noch immer die bekannteste und wertvollste Kryptowährung. Über die Jahre sind jedoch einige Probleme offenkundig geworden, wie z.B. der hohe Energieverbrauch und der niedriger Transaktionsdurchsatz. Um das Jahr 2016 kam eine neue Art von Protokollen auf, welche versprach diese beiden Probleme gleichzeitig zu lösen. Diese Protokolle basieren auf dem Proof-of-Stake (PoS) Mechanismus und verwenden gerichtete azyklische Graphen als Datenstruktur. Da es sich hier ebenfalls um Währungen handelt, spielt Sicherheit eine zentrale Rolle. Dies wirft die Frage auf, wie sicher Protokolle dieser Art wirklich sind. Diese Arbeit trägt zur Beantwortung bei, indem Hashgraph im Detail analysiert wird. Hashgraph ist ein vielversprechender Vertreter dieser Protokollart. Die verschiedensten Sicherheits- und Performanceangaben des Protokolls werden mithilfen eines im Zuge der Arbeit entwickelten und veröffentlichten Simulators überprüft. Der Simulator ermöglicht es, das Verhalten des Protokolls unter vier verschiedenen (Angriffs-)Szenarien zu untersuchen. Er bietet dazu umfangreiche Konfigurationsmöglichkeiten an, welche unzählige verschiedene Verläufe ermöglichen. Akteure/Akteurinnen agieren zufällig basierend auf einem veränderbaren Parameter, der Reproduzierbarkeit gewährleistet. Der Simulator selbst verfügt außerdem über eine grafische Benutzerobefläche, wobei Ergebnisse auch als Text-Dateien für weitere Analysen exportiert werden können. In keiner einzigen von tausenden Simulationen wurde der Konsensus-Mechanismus von Hashgraph gebrochen. Basierend auf der Tatsache das Nachrichten zur Synchronsiation beliebig schnell und an beliebige andere Knoten gesendet werden können, kamen jedoch Schwachstellen zu Tage. Diese Arbeit zeigt auf, dass es möglich ist eine widersprüchliche Transaktion zu einer bereits existierenden zu veröffentlichen und diese schneller bestätigt zu bekommen. Weiters wird belohnt, wer Synchronisationen zuerst mit ganz bestimmten Knoten durchführt, was zu einer Überlastung dieser Knoten führen kann. Die präsentierten Ergebnisse zeigen, dass diese Protokollklasse tatsächlich das Potential besitzt, zwei der grundelegenden Probleme von traditionellen Kryptowährungen zu lösen. Die Möglichkeit von Nachrichten-Spam im System kann dies jedoch zunichte machen und ist ein wichtiger Punkt in der Bewertung solcher Protokolle.

M. Vivekanandan, V. N. Sastry, U. Srinivasulu Reddy

No abstract is available for this record.

Ayman Alkhalifah, Alex Ng, Paul Watters, A. S. M. Kayes

In Ethereum blockchain, smart contracts are immutable, public, and distributed. However, they are subject to many vulnerabilities stemming from coding errors made by developers. Seven cybersecurity incidents occurred in Ethereum smart contracts between 2016 and 2018, which led to financial losses estimated to be over US$ 289 million. Reentrancy vulnerability was the cause of two of these incidents, and the impacts went far beyond financial loss. Several reentrancy countermeasures are available, which are based on predefined patterns that are used to prevent vulnerability exploitation before the deployment of a smart contract; however, several limitations have been identified in these countermeasures. Motivated by all these issues, the objective of this article is to help developers improve the cybersecurity of smart contracts by proposing a solution that calculates the difference between the contract balance and the total balance of all participants in a smart contract before and after any operation in a transaction that changes its state. Proof-of-concept implementations show that this solution can provide a detection and prevention mechanism against reentrancy attacks during the execution of any smart contract.

Abubakar Sadiq Sani, Ke Meng, Zhao Yang Dong

Motivated by recent Denial of Service (DoS) attacks at the control center and multiple remote power generation sites of a registered entity in the U.S. power grid, we seek to address the lack of sufficient real-time mutual authentication and secure communication between smart grid components. We introduce SComm, a real-time mutually authenticated secure communication framework that consists of a commitment-based enrolment protocol and a mutually authenticated key establishment protocol by which components can authenticate each other and carry out secure communication to prevent DoS attacks. Our framework applies a Zero-Knowledge Elliptic Curve Diffie-Hellman (ZK-ECDH) to establish a unique cryptographic session key for secure communication. We analysed our framework with respect to its security and performance, and the results show that our frame-work enhances the security of components and communication in real-time to efficiently deal with unauthentication and DoS attack. As proof of concept, we apply our framework to mitigate the DoS attacks at the registered entity.

Djilali Moussaoui, Benamar Kadri, Mohammed Feham, Boucif Ammar Bensaber

Among the important challenges for Vehicular Adhoc Network (VANET) Security and Privacy. Most of the solutions for privacy in vanet are based on pseudonyms. And the pseudonyms are digital certificates with very limited information, valid for a short time, and hide the identity of the vehicle. The pseudonym operations (issuing, changing, and revoking) are centralized by a certification authority. In our paper, we propose a fully distributed management for pseudonyms in VANETs. We use the blockchain technology to perform the different operations related to pseudonyms. Our proposal use two blockchains, one for registering pseudonyms, the second for revoked ones. The vehicles are considered as miners in the blockchain. Our approach makes the vehicles in VANET more autonomous in managing the security, and reduce the exchanged data with a centralized authority (Certificate Authority-CA).