PMQC: A privacy-preserving multi-quality charging scheme in V2G network

Multi-quality charging, which provides the electric vehicles (EVs) with multiple levels of charging services, including quality-guaranteed service (QGS) and best effort service (BES), can guarantee the charging service quality for the qualified EVs in vehicle-to-grid (V2G) network. To perform the multi-quality charging, the evaluation on the EVs attributes is necessary to determine which level of charging service can be offered to this EV. However, the EV owner´s privacy such as real identity, lifestyle, location, and sensitive information in the attributes may be disclosed during the evaluation and authentication. In this paper, we propose a privacy-preserving multi-quality charging (PMQC) scheme in V2G network to evaluate the EVs attributes, authenticate its service eligibility and generate its bill without revealing the EVs private information. Specifically, we propose an evaluation mechanism on the EVs attributes to determine its charging service quality. With attribute based encryption, PMQC can prevent the EVs attributes from being disclosed to other entities during the evaluation. In addition, PMQC can authenticate the EV without revealing its real identity. Security analysis demonstrates that the EVs privacy mentioned above can be preserved by PMQC. Performance evaluation results show that PMQC can achieve higher efficiency in authentication compared with other schemes in terms of computation overhead.