@article {27382,
	title = {Joint Transaction Relaying and Block Verification Optimization for Blockchain Empowered D2D Communication},
	journal = {IEEE Transactions on Vehicular Technology},
	volume = {69},
	year = {2020},
	pages = {828 - 841},
	publisher = { IEEE},
	abstract = {Device to device (D2D) communication is a promising paradigm to support data sharing in the fifth generation (5G) small cell networks. However, D2D communication is more vulnerable to security and privacy threats due to direct wireless connection between the proximity devices. In this paper, we exploit blockchain technology to propose a new distributed and secure data sharing framework named D2D blockchain, where we deploy a set of Access Points (APs) to verify end users{\textquoteright} transactions. Besides, in order to enable the end users to receive the required data on time in the D2D blockchain, we propose two new schemes for the transaction confirmation procedure including a relay-assisted transaction relaying scheme and a Delegated Proof-of-Stake (DPoS) based lightweight block verification scheme. Furthermore, to incentivize the relay devices to help in relaying transactions in congested areas, and to encourage the verifiers to contribute their resources in block verification, we design a two-stage contract theory based joint optimization scheme. To measure the quality of the relayed transaction and the verified block, we formulate two models: value of transaction relaying (VoTR) and value of block verification (VoBV), and then design the optimal contract for each relay device and each verifier. Security analysis and numerical results illustrate that the proposed D2D blockchain and the designed joint optimization scheme are secure and efficient for data sharing among end users.},
	author = {Jiang, L. and Xie, S. and Maharjan, Sabita and Zhang, Yan}
}
@article {26975,
	title = {Blockchain Empowered Wireless Power Transfer for Green and Secure Internet of Things},
	journal = {IEEE Network},
	volume = {33},
	year = {2019},
	month = {09/2019},
	pages = {164-171},
	publisher = { IEEE},
	abstract = {Wireless power transfer is a promising approach to charge low-power IoT devices for energy replenishment. However, energy attacks from malicious IoT devices can result in significant energy loss to energy transmitters. In this article, we propose a new distributed and secure wireless power transfer architecture by utilizing blockchain. The proposed architecture includes two planes: the energy plane and blockchain plane. We further abstract three types of traffic flows, transaction flow, consensus flow and coin flow, to provide a profound insight into the workflow of blockchain. Furthermore, to obtain the optimal amount of transferred energy in the energy plane, and to resolve high operational overhead of the consensus process in the blockchain plane, we develop a contract theory based wireless power transfer scheme and a DPoS based lightweight consensus scheme, and design an efficient wireless power transfer mechanism by combining the two schemes. Illustrative results demonstrate that our proposed schemes offer significant energy loss reduction with moderate operational overhead.},
	author = {Jiang, L. and Xie, S. and Maharjan, Sabita and Zhang, Yan}
}
@article {26440,
	title = {Blockchain for Secure and Efficient Data Sharing in Vehicular Edge Computing and Networks},
	journal = {IEEE Internet of Things Journal},
	year = {2018},
	month = {10/2018},
	publisher = {IEEE},
	abstract = {The drastically increasing volume and the growing trend on the types of data have brought in the possibility of realizing advanced applications such as enhanced driving safety, and have enriched existing vehicular services through data sharing among vehicles and data analysis. Due to limited resource of vehicles, mobile edge computing integrated with vehicular networks gives rise to Vehicular Edge COmputing and Networks (VECONs) for providing powerful computing and massive storage resources. However, vehicular edge computing servers consisted of roadside units cannot be fully trusted, which may result in serious security and privacy challenges. We exploit consortium blockchain and smart contract technologies to achieve secure data storage and sharing in vehicular edge networks. These technologies efficiently prevent data sharing without authorization. In addition, we propose a reputation based data sharing scheme to ensure high-quality data sharing among vehicles. A three-weight subjective logic model is utilized for precisely managing reputation of the vehicles. Numerical results based on a real dataset show that our schemes achieve reasonable efficiency and high-level security for data sharing in VECONs.},
	author = {Kang, J. and Yu, R. and Huang, X. and Yu, M. and Maharjan, Sabita and Xie, S. and Zhang, Yan}
}
