RPoE: A Reputation-Aware Proof-of-Energy Blockchain Protocol for Electric Vehicle Energy Trading in IoEV

Decentralized energy trading among electric vehicles (EVs) and charging stations (CSs) still suffers from high energy consumption, low throughput, and heavy consensus overheads. We present Reputation-Aware Proof-of-Energy (RPoE), a lightweight consensus that combines an energy score (ES) and a reputation score (RS); nodes with RPoE above a threshold participate in validation, and the highest-scoring node proposes the block. To sustain participation, we introduce a budget-balanced incentive with a guaranteed participation floor and a proportional share derived from concave weights of normalized RPoE and exchanged energy; tunable parameters trade fairness for efficiency. Our security analysis provides formal guarantees of double-spend resistance, Sybil resistance (trust-authority-backed identities), liveness under bounded delays, and resilience to DDoS/eclipse through eligibility gating. On a multi-node Raspberry Pi (RPi) testbed, RPoE reduces CPU workload by 47%, bandwidth by 5%, and energy consumption by 10% relative to Practical Byzantine Fault Tolerance (PBFT), Proof-of-Stake (PoS), and Proof-of-Authority (PoA), while achieving higher throughput and lower confirmation latency. The incentive remains fair and balanced. In a 10-node study with a participation floor of 20%, Jain's Fairness Index (JFI) is 0.853 (values closer to 1 indicate more fair splits) and the Gini coefficient is 0.221 (values closer to 0 indicate more equal splits), demonstrating equitable and budget-balanced rewards that avoid dominance.