Towards secure and efficient blockchain-based peer-to-peer energy trading systems
Creators: name: Abdella, Juhar
Publisher: name: RMIT University
Year: 2024
Subjects: classificationCode: 460403
subject: Data security and protection
classificationCode: 460605
subject: Distributed systems and algorithms

description: With the advancement of renewable energy sources and small-scale power producers, the need for a decentralized Peer-to-Peer Energy Trading (P2P-ET) system has become more crucial than ever before. However, the traditional energy trading system is built on a centralized architecture that is not only confined to large energy generators and utilities, but also suffers from various types of challenges such as single point of failure, communication bottleneck, denial-of-service (DoS) attacks, integrity attacks, inefficiencies in payment settlement and transparency issues. Blockchain is expected to be one of the cornerstones of the next generation P2P-ET systems due to its robust decentralized architecture, immutable database, its ability to support electronic contracts and peer-to-peer payment transactions between anonymous untrusting entities without the need for a trusted mediator. The past few years have seen a significant amount of research effort going into blockchain-based P2P-ET systems. However, current blockchain-based P2P-ET solutions have not addressed some of the fundamental weaknesses of blockchain technology with respect to the requirements of P2P-ET such as architectural, performance, scalability and privacy challenges.

On the one hand, existing solutions rely on either public blockchains which are not only inconvenient for enforcing the operational, regulatory, business model and authentication requirements of P2P-ET systems, but also perform poorly or permissioned blockchains which do not scale to the large number of nodes and number of transactions required by P2P-ET systems. On the other hand, the privacy of bilateral contracts and the confidentiality of bids and offers is not addressed in comprehensive manner considering the complex nature of P2P-ET systems which consists of various stakeholders having different level of access privileges to sensitive data and involve heavy computation like market clearing. In this thesis, we propose a secure and efficient
blockchain-based P2P-ET system that addresses the aforementioned limitations. This study began with an investigation of the best architecture that satisfies the operational, regulatory, business model and authentication requirements of P2P-ET. Hence, we proposed a unified permissioned blockchain-based P2P-ET architecture (UBETA) that integrates three different types of energy markets, payment settlement and authentication functions. UBETA is based on a customized Ethereum blockchain and Istanbul Byzantine Fault Tolerance (IBFT) consensus. We then performed a real implementation and detailed performance evaluation of four mainstream consensus algorithms, namely PoW, Clique, Raft and IBFT based on various performance metrics
such as latency, throughput and success rate. The experimental results indicated that the IBFT-based system has 15x lower latency and nearly 2x throughput compared to PoW-based solutions and provides better scalability and success rate than Raft with the fail rate of IBFT increasing by only 11% while that of Raft increased by 20% when the number of nodes was increased from 20 to 60. In addition, compared to its nonunified counterpart, the unified design of UBETA reduces the latency and the number of transactions. Our implementation has been published on GitHub as a benchmark.

Following that, we proposed a hierarchical concurrent optimistic blockchain consensus protocol, called HiCoOB to tackle the performance and scalability issues of blockchain-based P2P-ET. HiCoOB consists of an optimistic local consensus and a deterministic global consensus that enable the concurrent execution of local and global transactions. Moreover, HiCoOB allows the local and global consensus to be coordinated by two distinct leaders, thereby reducing the overhead on the local leader node. HiCoOB also provides a synchronization method between the local and global consensus to avoid the double spending of energy or money that arises from interdependent client transactions. Experimental results indicated that HiCoOB achieves 87% higher
throughput than existing systems. Furthermore, it reduces the waiting time of the local transactions by a factor of 5x. Finally, HiCoOB has 10 times less overhead on the local leader node in terms of message exchange when compared to state-of-the-art systems. The third part of the thesis addresses the privacy concerns in the bilateral market. Specifically, we suggested a Multi-Level Privacy-Preserving system (MuLPP) that provides three levels of privacy: public-level, energy authority-level and participant-level, to protect user anonymity, energy price and energy amount privacy against the various entities in the system while also protecting fake energy offer attacks. MuLPP is based on blockchain smart contracts, RSA accumulators, public key aggregation and BLSbased multi-signature. We also propose PADPeC, a permissioned anonymous decentralized P2P off-chain communication protocol to enhance the performance of private energy negotiations. Experiments showed that MuLPP provides 75 to 100 times lower latency and PADPeC reduces the message-sending time and the number of message exchanges by a factor of 4123 and 7.88 respectively compared to existing systems. Finally, to address the privacy concerns in the pool market, we proposed VeDPriP: a Verifiable Decentralized Privacy Preserving System. VeDPriP is based on blockchain, Shamir’s secret sharing, homomorphic secret sharing and Pederson commitment. It allows performing bidding and market clearing in a decentralized manner without revealing the confidentiality of energy amounts to external parties and market operators. Mathematical proofs indicate that VeDPriP is correct and verifiable. VeDPriP reduces the communication complexity from O(n2) to O(n ·m) compared to current solutions where n and m are the number of users and auctioneers respectively. Experimental results showed that VeDPriP decreases the communication overhead of share distribution and energy commitment tasks by a factor of 2 and 70 respectively and has 62.5 times less computation cost for energy commitment than state-of-the-art.