MuLPP: A multi-level privacy preserving for blockchain-based bilateral P2P energy trading

Challenges pertaining to user anonymity and data privacy are among the major concerns in blockchain-based bilateral Peer-to-Peer Energy Trading (P2P-ET). However, existing solutions focus only on user anonymity and are severely exposed to fake energy offers that can lead to denial-of-service attacks. Moreover, the off-chain communication mechanism used for private energy negotiation is computationally inefficient. This paper proposes a Multi-Level Privacy-Preserving system (MuLPP) for blockchain-based bilateral P2P-ET that provides user anonymity, energy price and energy amount privacy while protecting against fake energy offers. To address the privacy concerns in a comprehensive way, MuLPP offers three levels of privacy: public-level, energy authority-level and participant-level. MuLPP is based on blockchain smart contracts, RSA accumulators, public key aggregation and BLS-based multi-signature to achieve user anonymity, data privacy, robustness against fake energy offers and security in off-chain negotiation. This paper also proposes a permissioned anonymous decentralized P2P off-chain communication protocol, known as PADPeC, to enhance the privacy and performance of off-chain energy negotiations. Experimental results conducted in a real environment indicate that MuLPP provides 75 to 100 times lower on-chain latency. On the other hand, PADPeC reduces the message-sending time and the number of message exchanges in the off-chain communication by a factor of 4123 and 7.88 respectively compared to the existing systems. Formal security verification conducted using AVISPA security verification tool also revealed that the system is secure against various attacks such as sybil, network flooding and fake energy offer attack. • Privacy is a major concern in blockchain-based bilateral energy trading and requires different levels of privacy including public-level, energy authority-level and participant-level. • The off-chain communication mechanism used for private energy negotiation is computationally inefficient. • RSA accumulator guarantees the anonymity of energy sellers while also protecting fake energy offers. • Public-key aggregation and stealth addresses help achieve an anonymous on-chain payment settlement. • BLS-based multi-signature and a permissioned anonymous decentralized P2P communication protocol, is used to enhance the security, privacy and performance of off-chain energy negotiations.