A Blockchain-Based Authentication Scheme for Energy Trading in Electric Transportation

Authentication between Electric Vehicle (EV) users and Battery Charging/Switching (BCS) stations is a significant problem for energy trading. Although there are many existing authentication schemes, cross-domain authentication for EV users and BCS stations from different domains (such as different regions, companies, manufacturers) has not been well addressed; several blockchain-based cross-domain authentication schemes have more than 11 times communication rounds and involve over 4 times exponentiation, scalar multiplications and bilinear pairing cryptographic operations; this leads to high communication and computational costs. This work aims to tackle this problem by using blockchain and certificate-based public-key cryptography. It proposes an authentication scheme that uses a blockchain ledger to record authentication materials across different domains. A two-stage smart contract is designed and deployed to verify the authentication materials before storing them permanently in the blockchain. A novel certificate-based authenticated key establishment (CB-AKE) protocol is proposed to authenticate EV users and BCS stations. Based on the theoretical analysis and practical evaluation on the security and performance, the proposed scheme can well address the cross-domain authentication problem with acceptable cost. Compared to benchmark schemes, the authentication latency of CB-AKE is decreased by at least 25% and the throughput of CB-AKE is increased by at least 34%.