Blockchain based reputation management, data storage and distributed revocation in vehicular energy networks in smart health care systems.

In vehicular energy networks (VENs) operating in smart health care systems (SHaCarS), reputation of vehicles, i.e., ambulances, plays an important role as all functions depend upon it including message sharing, energy trading, etc. Keeping this in view, this paper presents a reputation management scheme. To ensure that the proposed scheme is secure and transparent, Blockchain (BC) technology is used. In the proposed model, the registration of ambulances is performed through a certificate authority (CA). Later, a pseudo mechanism is designed using Elliptic Curve Digital Signature Algorithm, which ensures conditional anonymity and traceability. The ambulances are provided with the pseudo identities, which are mapped with the real identities to prevent disputes. Besides, the proposed scheme uses a Shamir secret sharing (SSS) algorithm to enable distributed revocation in BC based VENs operating in SHaCarS. In addition, the ambulances' reputation information is stored in interplanetary file system (IPFS) in an efficient manner. The hashes are generated by IPFS upon data storage, which are then stored in BC. The performance evaluation of the proposed system is done via extensive simulations. The results show 18–20% reduction in computational overhead and 35–40% reduction in storage overhead. The proposed system's robustness is tested by inducing the 51% attack and the replay attack. In addition, the security analysis of the smart contract is performed using Oyente. The results show that the system proposed for reputation management in the underlying work is robust and computationally efficient. [ABSTRACT FROM AUTHOR]