Proof of Work (PoW) powered blockchains currently account for more than 90% of the total market capitalization of existing digital cryptocurrencies. Although the security provisions of Bitcoin have been thoroughly analysed, the security guarantees of variant (forked) PoW blockchains (which were instantiated with different parameters) have not received much attention in the literature. This opens the question whether existing security analysis of Bitcoin's PoW applies to other implementations which have been instantiated with different consensus and/or network parameters. In this paper, we introduce a novel quantitative framework to analyse the security and performance implications of various consensus and network parameters of PoW blockchains. Based on our framework, we devise optimal adversarial strategies for double-spending and selfish mining while taking into account real world constraints such as network propagation, different block sizes, block generation intervals, information propagation mechanism, and the impact of eclipse attacks. Our framework therefore allows us to capture existing PoW-based deployments as well as PoW blockchain variants that are instantiated with different parameters, and to objectively compare the tradeoffs between their performance and security provisions.

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On the Security and Performance of Proof of Work Blockchains

The concept of the Internet of Vehicles (IoV) has attracted the attention of many sectors such as the automotive industry, academia, engineering, etc., offering a wide variety of benefits, such as reduced congestion, safer driving, and less pollution. However, since the deployment of IoT based devices is in an open field, the IoV environments can be a vital issue in the absence of security protections. In this paper, we propose an efficient authentication scheme over blockchain, named EASBF, for secure fog computing-enabled internet of vehicles. Specifically, the proposed EASBF scheme consists of five phases: initialization, registration, mutual authentication, and exchanging keys, consensus, and certificate update. Based on the elliptic curve cryptography, one-way hash function, and blockchain technology, the EASBF scheme can achieve confidentiality, integrity, authenticity, privacy, anonymity, non-repudiation, and perfect forward secrecy. The EASBF scheme is robust against cyber attacks, including, DDoS attack, replay attack, man-in-the-middle attacks, identity theft attack, traffic analysis attack, masquerading attack, and session key disclosure attack. Both the AVISPA tool and the random oracle model are used in security analysis. Finally, we demonstrate the effectiveness of the EASBF scheme in terms of two performance metrics, namely, computation overhead, communication overhead, and storage overhead.

EASBF: An efficient authentication scheme over blockchain for fog computing-enabled internet of vehicles

Vehicular ad hoc networks (VANETs) have become an important part of the intelligent transportation system that aims to promote communication among vehicles to ensure vehicular safety and improve the driving experience. In VANETs, signed messages need to be authenticated by roadside units in a very short time. Certificateless aggregate signature (CLAS) scheme has been considered as one of the promising solutions to solve the problem of limited network bandwidth and computing power in VANETs environment. In this article, we propose an efficient pairing-free CLAS, named eCLAS, which is suitable for communication between vehicle to infrastructure. The aggregated signature allows individual signature on different messages from different vehicles to be aggregated into one short signature. In the random oracle model, the security of the scheme is proved by the adaptive selection message attack and the difficulty of computation of discrete logarithm problem on the elliptic curve. Additionally, the security analysis shows that the proposed scheme can meet security requirements in VANETs. Compared with existing schemes, the result demonstrates that our scheme has obvious advantages in signature verification, thereby granting it better applicability.

eCLAS: An Efficient Pairing-Free Certificateless Aggregate Signature for Secure VANET Communication

Vehicular ad hoc networks (VANETs) have become an important part of the intelligent transportation system that aims to promote communication among vehicles to ensure vehicular safety and improve the driving experience. In VANETs, signed messages need to be authenticated by roadside units in a very short time. Certificateless aggregate signature (CLAS) scheme has been considered as one of the promising solutions to solve the problem of limited network bandwidth and computing power in VANETs environment. In this article, we propose an efficient pairing-free CLAS, named eCLAS, which is suitable for communication between vehicle to infrastructure. The aggregated signature allows individual signature on different messages from different vehicles to be aggregated into one short signature. In the random oracle model, the security of the scheme is proved by the adaptive selection message attack and the difficulty of computation of discrete logarithm problem on the elliptic curve. Additionally, the security analysis shows that the proposed scheme can meet security requirements in VANETs. Compared with existing schemes, the result demonstrates that our scheme has obvious advantages in signature verification, thereby granting it better applicability. 

Wireless sensor networks (WSNs) are gaining traction in day to day applications where data has to be gathered in hostile environments using low computing power sensors. As these sensors are deployed in hostile environments, strong authentication mechanisms are essential to guarantee the safety and security of the data being transferred. But, these strong authentication mechanisms are computationally heavy for the low power sensors. So, there is a need for a lightweight and secure authentication protocol for WSNs. Applications of these sensor ranges from healthcare to oil and exploration. The security of the data being gathered and transmitted is of utmost importance as they can correlate to life and death situations in some instances. So, employment of extremely secure schemes is a necessity but all these schemes are computationally very expensive and require powerful hardware. The sensors used in WSN are designed for low power environments, and longevity and hence do not possess these hardware resources to secure the communication. Hardware-level, as well as lightweight operations, have to employ for securing the communication. This procedure also preserves the integrity of data being gathered and transmitted by the sensor through these WSNs.

A Lightweight And Secure Authentication Protocol for WSN.

With the rapid technological advancement of the universal internet of vehicles (UIoV), it becomes crucial to ensure safe and secure communication over the network, in an effort to achieve the implementation objective of UIoV effectively. A UIoV is characterized by highly dynamic topology, scalability, and thus vulnerable to various types of security and privacy attacks (i.e., replay attack, impersonation attack, man-in-middle attack, non-repudiation, and modification). Since the components of UIoV are constrained by numerous factors (e.g., low memory devices, low power), which makes UIoV highly susceptible. Therefore, existing schemes to address the privacy and security facets of UIoV exhibit an enormous scope of improvement in terms of time complexity and efficiency. This paper presents a lightweight authentication and batch verification scheme (LABVS) for UIoV using a bilinear map and cryptographic operations (i.e., one-way hash function, concatenation, XOR) to minimize the rate of message loss occurred due to delay in response time as in single message verification scheme. Subsequently, the scheme results in a high level of security and privacy. Moreover, the performance analysis substantiates that LABVS minimizes the computational delay and has better performance in the delay-sensitive network in terms of security and privacy as compared to the existing schemes.

LABVS: Lightweight Authentication and Batch Verification Scheme for Universal Internet of Vehicles (UIoV)

Vehicular ad-hoc networks (VANETs) inflict smart traffic control using information exchange (i.e., warning messages, routing and network discovery messages) with nearby vehicles immediately in a highly dynamic environment. Prior approaches have proposed several routing computations and discovery techniques using prediction, direction aware, and hello message assisted algorithms. However, most of them do not perform adequately in real-life traffic situations and have various concerns i.e., broadcast storming, unpredictable network dynamics, fixed-route life-time problem, non-linear real-world traffic, high routing overhead, and low packet delivery ratio. Clustering architecture in vehicular scenarios improves resource utilization, network scalability and flow of data between communicating vehicles but stable cluster formations is also a challenging task in real-life traffic situations. Therefore, in this paper, we proposed a cosine similarity based selective broadcast routing protocol, also known as CSBR, which leverages non-linear cluster formation ability using cosine similarity index. Distinct clusters and the coordinating vehicles assist each other in finding the most suitable path to reach the destination. Additionally, a probabilistic forwarding approach is used to disseminate routing messages further in the network. The outcomes exhibit that the proposed scheme improved 5-10% packet delivery fraction (PDF), minimizes average delay approximately 25%, up to 10% low communication overhead, improved throughput upto 5-10%, and less neighbour discovery messages overhead compared to the existing broadcast routing protocols in VANETs.

CSBR: A Cosine Similarity Based Selective Broadcast Routing Protocol for Vehicular Ad-Hoc Networks

Authentication of users and devices is one of the security issues on the internet of things (IoT). Traditionally, the authentication system is based on a centralized server, which makes it prone to various security threats and potential attacks; also, the stored data can tamper. In this paper, existing issues are resolved using Blockchain. IoT devices do not have much computational power. Blockchain technology, which uses the Proof-of-Work concept, consumes a lot of energy, which makes it not suitable for IoT devices. A new efficient scheme to reduce the computational energy of the devices is discussed, along with an authentication scheme that uses no centralized servers and makes IoT devices interact directly with Blockchain is designed and is implemented. The smart contract concept is used in this scheme, which provides users the flexibility to design there own rules for authentication.

Efficient Authentication Scheme Using Blockchain in IoT Devices

The fully dynamic dense environment of the Internet of Vehicles (IoV) and conditions like high traffic jams, collisions, and uneven road conditions increase the communication messages. Consequently, the computation and communication costs of the IoV network are increased. Therefore, IoV needs a lightweight and efficient security solution along with effective communications. Existing state-of-the-art schemes in IoV are generally based on cryptographic methods that use session keys, public keys, elliptic curves, and Message Authentication Codes (MAC). In contrast to the other schemes, MAC-based schemes provide feasible security solutions having high performance with less overhead. The existing MAC-based authentication schemes are vulnerable to the key disclosure issue along with some security attacks such as side-channel attacks, Distributed Denial of Services (DDoS), etc. Due to the side channel attack, a data leakage problem occurs, which is a serious concern in security and privacy facets. We propose a novel MAC-based authentication scheme (NoMAS) that mitigates the above-discussed challenges and provides all the benefits of MAC-based schemes. The NoMAS scheme offers a solution for key disclosure issues by providing Hard Key and Soft Key Updates (HKU and SKU) and data leakage problems using encryption along with high performance. It reduces the computational overhead maximum to 99.60% and the communication overhead maximum to approximately 81% compared to the existing schemes. In the security analysis, We have provided the formal security proof using BAN logic and the ProVerif tool and verified the correctness of the scheme.

Himani Sikarwar

Papers

LABVS: Lightweight Authentication and Batch Verification Scheme for Universal Internet of Vehicles (UIoV)

A Lightweight And Secure Authentication Protocol for WSN.

CSBR: A Cosine Similarity Based Selective Broadcast Routing Protocol for Vehicular Ad-Hoc Networks

Efficient Authentication Scheme Using Blockchain in IoT Devices

A Novel MAC-Based Authentication Scheme (NoMAS) for Internet of Vehicles (IoV)