Department of Computer Science and Information Systems

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    An efficient and scalable byzantine fault tolerant consensus for vehicular networks
    (IEEE, 2025) Alladi, Tejasvi
    Vehicular networks represent a new distributed system paradigm that requires robust fault tolerance to ensure reliable operation. As a burgeoning area of research, the scalability and optimization of consensus mechanisms for these networks are critical. Traditional Byzantine Fault Tolerant (BFT) algorithms like PBFT are not inherently optimized for the localized needs of vehicular networks, suffering from scalability issues due to their global nature and high messaging complexity. In response, we introduce a two-tiered consensus framework that refines PBFT for the specific context of vehicular networks. By organizing nodes into clusters based on geographic proximity, our approach reduces messaging complexity from O(n2) to O(n1.5), significantly improving scalability. The framework distinguishes between local and global state transitions, adding two phases to the PBFT protocol to manage these efficiently. This tailored consensus process aligns with the localized communication patterns of vehicular networks, enhancing both efficiency and scalability. The framework addresses the critical challenges of traditional BFT algorithms in vehicular networks, offering a solution that is both scalable and resilient. It is a step toward enabling vehicular networks to fulfil their potential as a reliable component of modern distributed systems.
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    Layered blockchain-based mobile crowdsensing architecture: exploring privacy and scalability challenges across layers
    (Springer, 2025-04) Bhatia, Ashutosh; Tiwari, Kamlesh
    Blockchain technology has emerged as a transformative solution for addressing the limitations of traditional Mobile CrowdSensing (MCS) systems, which rely on centralized architectures. Despite its promise, the integration of blockchain into MCS introduces challenges related to privacy, scalability, and system efficiency. This paper presents a comprehensive layered architecture for enhancing blockchain-based MCS systems (BMCS), focusing on two critical dimensions: privacy and scalability. By categorizing challenges and proposed mitigation strategies, the study explores privacy risks arising from blockchain transparency and evaluates privacy-preserving mechanisms, including zero-knowledge proofs, multiparty computation, and homomorphic encryption, to protect sensitive data in decentralized environments. Scalability constraints, such as limited transaction throughput and resource intensity, are presented with targeted solutions that reduce on-chain loads and improve performance. The findings contribute actionable insights to advance BMCS systems, charting a path for resilient and scalable decentralized ecosystems.
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    Smartchain: a smart and scalable blockchain consortium for smart grid systems
    (IEEE, 2019) Dua, Amit
    Smart grid (SG) provides a peer-to-peer energy trading mechanism wherein the electric vehicles (EVs) can trade for energy with their peers using the information and communication technologies. However, the dependence on third party for coordinating the energy trading decisions leads to a bottleneck for any distributed environment. Therefore, blockchain technology can provide a privacy-preserving and effective consensus mechanism without the control of trusted third party. Although blockchain provides inherent secure framework for transactional process, but the this security is because of computational complexity enforced. In SG environment, the conventional blockchain process could not be employed due to limited computational resources with EVs, which makes it difficult to solve the tough computational puzzles to validate the transactions. On the other hand, any compromise on the computation difficulty makes it more vulnerable to various types of attacks. Therefore, in this paper, SmartChain: a blockchain inspired smart and scalable ledger framework which does not require much computational complexity is designed for secure peer-to-peer energy trading in SG ecosystem. The proposed framework is evaluated using the parameters such as execution and validation time. The results obtained depict the superiority of SmartChain in contrast to the conventional blockchain process.
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    Security of Cryptocurrencies in blockchain technology: State-of-art, challenges and future prospects
    (Elsevier, 2020-08) Gupta, Shashank; Dua, Amit
    In contemporary era of technologies, blockchain has acquired tremendous attention from various domains. It has wide spectrum of applications ranging from finance to social services and has greatly influenced the emerging business world. Since, blockchain technology is getting embedded in the e-commerce services, the cryptocurrencies are gaining huge prevalence. Bitcoin and ethereum are few such crypto currencies, which have utilized decentralized nature of blockchain. Blockchain can be considered as a distributed database system containing immutable ledgers, which are prone to attack by malicious users. Although, from the initial digital currency to the present smart contract, the utilities of blockchain have been harnessed, the innovative technology has to rely on cryptography for its security. There are several reports, which emphases on the vulnerabilities and security of blockchain, however, there is a lack of a comprehensive and methodical survey in both application and technical views. In this survey article, the authors cover various aspects related to blockchain including its taxonomies and the situations in which a particular category of blockchain should be applied. The authors also focusses on the structure of blockchain and the working of the ongoing transactions in the cryptocurrency network. In addition, the authors also specify various categories of consensus protocols, smart contracts, forks, techniques for generating the consensus. A detailed taxonomy of blockchain along with their features and related real-world applications is also discussed. In addition, existing key platforms of blockchain related to the cryptocurrencies, hyperledger and multichain are also discussed. Existing emerging vulnerabilities of blockchain related to the recent attacks on bitcoin and etherum is also presented along with the defensive methodologies and future trends in blockchain.
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    Trustless Two-Factor Authentication Using Smart Contracts in Blockchains
    (IEEE, 2019) Bhatia, Ashutosh
    Two-factor authentication (2FA) is widely prevalent in banking, emails and virtual private networks (VPN) connections or in accessing any secure web service. In 2FA, to get authenticated the users are expected to provide additional secret information along with the password. Typically, this secret information (tokens) is generated by a centralized trusted third party upon receiving an authentication request from users. Thus, this additional layer of security comes at the cost of inherently trusting the third party for their services. The security of such authentication systems is always under the threat of the trusted party is being compromised. In this paper, we propose a novel approach to make server authentication even more secure by building 2FA over the blockchain platform which is distributed in nature. The proposed solution does not require any trusted third party between claimant (user) and the verifier (server) for the authentication purpose. To demonstrate the idea of using blockchain technology for 2FA, we have added an extra layer of security component to the OpenSSH server a widely used application for Secure Shell (SSH) protocol.
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    A Blockchain based Solution to Know Your Customer (KYC) Dilemma
    (IEEE, 2019) Bhatia, Ashutosh
    Know Your Customer (KYC) is done as a mandatory entry step into any financial institution. However, even today the amount of manual intervention involved in the process is staggering. Often the data is centrally stored, and the computer programs acting are also centrally governed thus are not tamperproof making them susceptible to vulnerabilities and attacks. Different organizations do not have a unified application where the KYC information can be seamlessly shared between them without any risk of repudiation from any of the participating organizations. Our application, that is based on blockchain technology, aims to provide this platform as a service to financial institutions as an electronic-KYC solution, in the process of making the life of the end consumer easier
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    A Fast, Secure and Distributed Consensus Mechanism for Energy Trading Among Vehicles using Hashgraph
    (IEEE, 2020) Bhatia, Ashutosh
    Energy trading among inter vehicles (V2V) offers an efficient response to most of the problems presented by future electricity supply. V2V is often envisioned as a peer-to-peer (P2P) model of electric mercantilism for electric vehicle (EV) merchandising. With security vulnerability increasing, confidence in secured third parties is declining. Blockchain is becoming increasingly common as it provides a system for privacy conservation and efficient agreement without the need for trusted third parties. However, all operations in such a scheme are restricted by memory, time, computing capital, energy etc. and it is quite obvious that the mechanism for blockchain agreement is not sufficient to address all of them. In this paper, we present an alternative to the blockchain using Hashgraph which is scalable, fast, fault-tolerant and fair. It is efficient, inexpensive, and DoS resistant fulfilling the requirement of V2V energy trading
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    Securing IoT Applications using Blockchain: A Survey
    (2020-06) Bhatia, Ashutosh
    The Internet of Things (IoT) has become a guiding technology behind automation and smart computing. One of the major concerns with the IoT systems is the lack of privacy and security preserving schemes for controlling access and ensuring the security of the data. A majority of security issues arise because of the centralized architecture of IoT systems. Another concern is the lack of proper authentication and access control schemes to moderate access to information generated by the IoT devices. So the question that arises is how to ensure the identity of the equipment or the communicating node. The answer to secure operations in a trustless environment brings us to the decentralized solution of Blockchain. A lot of research has been going on in the area of convergence of IoT and Blockchain, and it has resulted in some remarkable progress in addressing some of the significant issues in the IoT arena. This work reviews the challenges and threats in the IoT environment and how integration with Blockchain can resolve some of them.
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    E-Governance: A Tendering Framework Using Blockchain With Active Participation of Citizens
    (IEEE, 2020) Bhatia, Ashutosh
    E-governance, i.e., the use of information technology for government activities to provide services, exchange information, etc. are becoming increasingly popular. One such area of e-governance is e-tendering. While e-tendering makes the tendering process more efficient, a trust deficit remains between the citizens and the government, due to the centralized management of the whole tendering process. Several research works provide a decentralized solution to make the process of e-tendering more secure, transparent, and fair. However, in the present time, the government posts the problems/issues currently they are dealing with; and seems interested in taking the suggestions from the citizens to make the better solution for the problem. Thus, in this paper, a permissioned blockchain-based approach to provide a transparent and fair tendering system with citizens' active participation and tracking of funds is presented. In the proposed scheme, the citizens can see the tendering activities transparently and give ideas and suggestions to solve the government's posted problems and receive a due credit of that contribution is a fair manner.
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    Decentralized Online Voting using Blockchain and Secret Contracts
    (IEEE, 2021) Bhatia, Ashutosh
    Voting is a complex process with a lot depending on it. Building an e-voting system that can guarantee anonymity, verifiability, and transparency together is a challenging task. Continuous efforts are being made to improve the voting system to achieve these properties. Recently, blockchain has hit the technology space with many promises, especially to make verifiable and transparent decentralized systems. However, a major challenge faced with blockchain-based e-voting systems is to achieve the users' anonymity while ensuring only authorized voters should be able to vote, and that too only once. To address these issues, this paper proposes a blockchain-based e-voting system with secret contracts. We have used Enigma (a secure multiparty computation platform) to design secret contracts. The proposed system meets most of the features required to conduct free and fair voting electronically.