Follow blockchain research across journals, conferences, and preprint repositories.
2,611 results · page 50 of 109
Fardin Ahmed Niloy, Nozib Ud Dowla, Md Samiul Alam, Jobair Hossain · 7 authors
No abstract is available for this record.
Zhanwen Chen, Kazumasa Omote
No abstract is available for this record.
Ethan Heilman
While distributed databases offer great promise their decentralized nature poses a number of security and privacy issues. In what ways can parties misbehave? If a database is truly distributed can a malicious actor hide their misdeeds by presenting conflicting views of the database? Can we overcome such deceit and either prevent it by eliminating trust assumptions or detect such perfidy and hold the malicious party to account? We study these questions across two distributed databases: RPKI (Resource Public Key Infrastructure), which is used to authenticate the allocation and announcement of IP prefixes; and Bitcoin, a cryptocurrency that utilizes a permissionless database called a blockchain to track the transfer and ownership of bitcoins. The first part of this dissertation focuses on RPKI and the potential of RPKI authorities to misbehave. We consider the methods, motivations, and impact of this misbehavior and how an RPKI authority can present inconsistent views to hide this misbehavior. After studying the problem we propose solutions to detect and identify such misbehavior. Now we turn our attention to Bitcoin. We look at ways an attacker can manipulate Bitcoin's Peer-to-Peer network to cause members of the network to have inconsistent views of Bitcoin's blockchain and subvert Bitcoin's core security guarantees. We then propose countermeasures to harden Bitcoin against such attacks. The final part of this dissertation discusses the problem of privacy in Bitcoin. Many of the protocols developed to address Bitcoin's privacy limitations introduce trusted parties. We instead design privacy enhancing protocols that use an untrusted intermediary to mix \aka anonymize, bitcoin transactions via blind signatures. To do this we must invent a novel blind signature fair-exchange protocol that runs on Bitcoin's blockchain. This dissertation favors a dirty slate design process. We work to layer protections on existing protocols and when we must make changes to the underlying protocol we carefully weigh compatibility and deployment considerations. This philosophy has resulted in some of the research described in this dissertation influencing the design of deployed protocols. In the case of Bitcoin our research is currently used to harden a network controlling approximately a trillion dollars.
Adeeba Naaz, T. V. Pavan Kumar B, Maria Francis, Kotaro Kataoka
Authentication while maintaining anonymity when availing a service over the internet is a significant privacy challenge. Anonymous credentials (AC) address this by providing the user with a credential issued by a trusted entity that convinces the service provider (SP) that the user is authenticated but reveals no other information. The existing AC schemes assume a single trusted authority (certifier) that validates all the user attributes. In practice, however, a user may require different attributes to be attested by different certifiers. This means that the user has to get multiple credentials, increasing the burden on theSPwho has to verify each one of them. Moreover, complete anonymity can be misused. We propose adecentralized threshold revocable anonymous credential (DTRAC)scheme over blockchains that supports – a) attestation of attributes by multiple certifiers, and b) anonymity revocation through a set of distributed openers, by integrating threshold opening to the state-of-the-art threshold anonymous credential issuance scheme, Coconut [34]. DTRAC generates a single credential on attributes that are attested by multiple certifiers, freeing the SP from the hassle of verifying multiple credentials. We analyze the security of DTRAC formally in the universal composability (UC) framework. We also implement a prototype on Ethereum using smart contracts and give a detailed analysis of its performance.We compare the verification time for credentials with attributes attested by multiple certifiers in both DTRAC and Coconut and see that in terms of execution time and gas consumption, DTRAC performs significantly better than Coconut. It also scales better, with the performance gain of DTRAC over Coconut increasing linearly with the number of certifiers.
Yang Han, Dawei Xu, Jiaqi Gao, Liehuang Zhu
No abstract is available for this record.
Khushi Patel, Dipak Ramoliya, Kashish Sorathia, Foram Bhut
No abstract is available for this record.
Rishikesh Choudhari, Meghana Shivakumar, Shreyas Nandavar, Shruti Maigur · 7 authors
No abstract is available for this record.
Xingyu Zeng, Zhang Hua, Chaosong Yan, Zhao Liu · 5 authors
Blockchain technology is known as a decentralized, distributed ledger that records digital asset. It has been applied in numbers of aspects of society, including finance, judiciary and commerce. Ethereum is referred to as the next generation decentralized application platform. It is one of the most popular blockchain platforms that supports smart contracts. Smart contract is a set of codes that sored on blockchain and can be called and created as turing-complete programs running on the blockchain. Developers use smart contracts to build decentralized applications (Dapp) which has widely used cryptocurrency related project. As smart contracts become more popular and more valuable, they are faced with more risk of being hacked. As a result that smart contracts cannot be modified once deployed on the blockchain, it is a great challenge to fix and update deployed vulnerable contract which can lead to a huge loss of cryptocurrency and financial disorder. In this paper, we focus on Integer Bugs in Ethereum Smart Contracts and present ISmart, which protects deployed smart contracts against attacks caused by Integer Bugs. We implemented ISmart based on go-ethereum, a Ethereum client written in Go, by adding a simplified taint analysis component. In our preliminary, ISmart can prevent attacks accurately with little runtime overhead.
Utz Nisslmueller, Klaus-Tycho Foerster, Stefan Schmid, Christian Decker
No abstract is available for this record.
Janardan Krishna Yadav, Srinivas Jangirala, Deepika Verma, Shashi Srivastava · 5 authors
No abstract is available for this record.
Srijanee Mookherji, Vanga Odelu, Rajendra Prasath
No abstract is available for this record.
N. Sundareswaran, S. Sasirekha
No abstract is available for this record.
Mahima Pawar, Mansi Dabriwal, Raj Rathi, Shrey Kumar Sinha · 5 authors
No abstract is available for this record.
Kun Liao
In this paper, a variety of cloud service combinations is used to form the control core of a smart home, realize data forwarding, storage, and analysis in the cloud, and complete the remote management of smart home devices. This paper studies the secure access control of smart home data combined with the blockchain technology and password technology to realize the secure and efficient access control of smart home data. The system can achieve the goal of independent research and development. Aiming at the problem that the access control of a smart home is generally managed by third‐party authorized institutions and there is an unauthorized access, a blockchain‐based smart home (BSH) access control scheme is proposed. The scheme extends the attribute‐based access control model (ABAC) and applies the blockchain technology to the smart home ABAC model to realize fine‐grained access control. In the scheme, the resource provider first publishes the access control policy of the resource to the blockchain. If the resource visitor wants to access the resource, he needs to submit an access request to the blockchain and use an SM2 threshold signature to process the transaction proposal. The endorsement peer node in the blockchain runs the access control policy smart contract to decide whether to grant access rights. This scheme can ensure that resource providers can participate in all the processes of access control and avoid the risk of unauthorized access caused by the centralized management of the third party. Finally, the simulation experiment is carried out on the Hyperledger Fabric alliance chain development platform. The results show that the BSH access control scheme has good applicability in the smart home scenario.
Xiangdong Kong, Meng Shen, Zheng Che, Congcong Yu · 5 authors
No abstract is available for this record.
G. Megala, Prabu Sevugan, Ramarathnam Venkatesan
Although electronic voting has been used for many decades, electoral organizations are still adopting it. Despite technologies that preserve the secrecy, authenticity, and privacy of data, vote-rigging and privacy breaches remain a risk in e-voting systems. Blockchain is a distributed technology that underpins bitcoin. It appears to be a fit for digital election systems, as it provides a chance to keep data secret and prohibit data manipulation. But blockchain alone is not enough to address other concerns that come up during elections such as how to make sure that the person voting has the right to do so while keeping their identity disconnected from their vote. The user can safely vote from the three-levels of authentication: OTP, QR codeshare, and blockchain. Here, the system contains a secured timestamp and the hashcode which is used to identify attacks on the distributed server. These protected services provide secure vote casting and remedies for security issues. The legal limitations are also analyzed in the blockchain distributed ledger.
Elham Shammar, Ammar T. Zahary, Asma A. Al-Shargabi
The Internet of Things (IoT) is emerging from its infancy and establishing itself as a component of the future Internet. However, the ability to manage a huge number of IoT devices is one of the IoT technical challenges. To implement access control, traditional schemes typically rely on a trusted central organization. Traditional centralized access control systems of the IoT lead to the shortcomings of a single point of failure, low overall system efficiency, and ethical and privacy issues. To overcome such challenges, an attribute‐based access control model using Hyperledger Fabric blockchain (ABAC‐HLFBC) is proposed in this paper. By adopting ABAC, it is no longer to create access control lists (ACLs) or assign roles to all system users. Instead, ABAC grants access based on the attributes presented by the target. No one is permitted access unless he/she possesses sufficient attributes that correspond to the access policy. The Hyperledger Fabric Raft consensus mechanism has been used to verify the transaction on the proposed model because it has a demanding feature for faster and less complicated consensus in comparison to the Kafka ordering service. To evaluate the proposed model, it has been tested against the most recent previous work, called fabric‐iot model. The proposed model has been tested and evaluated in two parts. The first part tests the cost time using a client test program written in Golang. The second part tests the latency and throughput using the Hyperledger Caliper benchmark tool. Results show that the proposed model efficiently outperforms the previous work in terms of the performance metrics mentioned above.
Rongyu Xiao, Guozi Sun, Jiale Yang, Yao Wang · 5 authors
Public chains represented by Bitcoin and Ethereum do not require users to use their real names, and transaction data are open to the whole network. Analysed based on this, researchers have achieved the deanonymization of blockchain transactions to a certain extent. Based on the existing blockchain transaction privacy protection scheme, the true link relationship between the transaction sender and receiver is hidden, which brings difficulties to regulation. In this paper, we propose a cryptocurrency mixing service RBSmix, which allows users to reestablish their financial privacy in Bitcoin and related cryptocurrencies. RBSmix, through blind signature to prevent attackers from linking input and output addresses, by the threshold secret sharing algorithm, encryption technology, and a regulation team, combined with the idea of voting, tracks the source of funds for illegal addresses. Experiments show that the scheme scales to large numbers of users and can provide users with better privacy protection.
Olayemi Mikail Olaniyi, Eustace M. Dogo, Bello Kontagora Nuhu, Horst Treiblmaier · 6 authors
No abstract is available for this record.
Jingzhe Wang, Balaji Palanisamy
No abstract is available for this record.
Aanchal Mani, Samarjeet Patil, Soham Sheth, Lakshmi Sudha Kondaka
Blockchain is a distributed system that confirms security and reliability. It has started a new era of a solid and consensus system. Because of blockchain's emphasis on security, many other operations and processes are adopting the same reliable approach. Almost all processes and operations are now encouraged to be computed electronically in the digital Ethereum network that has been presented. In the current situation, we have seen what the conduction of elections has done to the worsening situation of the Covid-19 Pandemic. The proposed system uses an Ethereum network on a blockchain platform to implement a college voting system, making use of the Aadhar API. E-voting will help to support transparency and voters' trust to reduce corruption and unreliability in the voting processes. The use of this system will allow a voter to vote from home while also having the assurity that this process is completely secure and reliable due to the use of blockchain technology.
Sudeep Tanwar
No abstract is available for this record.
Zhihao Zeng, Xiaoning Zhang, Zixiang Xia
The development of fifth‐generation (5G) mobile communication technology has become a major driver to the growth of Internet of Things (IoT) applications. As a promising networking paradigm, software‐defined networking (SDN) makes IoT more flexible and agile by decoupling control plane from data plane. With a large number of heterogeneous devices accessing to the network, we need to divide the network into several domains and each domain is managed by an SDN controller. Controllers share topologies with each other to form global view of the entire network, which is used for crossing‐domain path routing. However, crossing‐domain routing requires global trust between multiple controllers. The reason is that if the malicious controller shares misleading topologies, the rest of controllers may calculate mistaken crossing‐domain paths. As a result, packets are forwarded to the domain that is managed by the malicious controller and dropped deliberately, which is known as the black‐hole attack. To this end, we present a blockchain‐based architecture to ensure secure routing among multiple domains in SDN‐enabled IoT networks. All SDN controllers are equipped with blockchains, and they upload abstract topologies to the blockchain via the smart contract. Thus, the genuine view of the entire network can be gained from the blockchain due to its consensus and immutability. In addition, we use the concept of reputation that consists of the local reputation and the global reputation to further protect routing reliability, and the global reputation is reserved in the blockchain. Compared with benchmark architectures, the emulation results show that our proposed method can effectively build trust between multiple controllers and ensure secure routing among multiple domains.
Francisco Assis Moreira do Nascimento, Fabiano Hessel
No abstract is available for this record.