Advances in Science, Technology and Engineering Systems Journal Vol. 7, No. 3, 106-115 (2022) www.astesj.com Special Issue on Innovation in Computing, Engineering Science & Technology ASTES Journal ISSN: 2415-6698 Secured Multi-Layer Blockchain Framework for IoT Aggregate Verifica- tion Ming Fong Sie, Jingze Wu, Seth Austin Harding, Chien-Lung Lin, San-Tai Wang, Shih-wei Liao * Department of Computer Science and Information Engineering, National Taiwan University, Taipei, 106, Taiwan ARTICLE INFO ABSTRACT Article history: Received: 27 March, 2022 Accepted: 25 May, 2022 Online: 04 June, 2022 Keywords: IoT Blockchain ID-based Signature Aggregate Verification Digital Provenance Supply Chain Management Technologies designed for digital provenance, especially the Internet of Things (IoT) and blockchain, may allow for security, transparency, and traceability in the global supply chain. However, upstream nodes in the supply chain that work for large-scale production suppliers are not considered. In addition, most IoT blockchain systems adopt an ID-based signature scheme that may affect the efficiency of IoT devices. We propose using aggregate verification to improve the security and efficiency of ID-based verification, reduce network traffic on the blockchain, and transfer computing overhead to aggregator nodes. This paper implements a multi-layer blockchain for Agriculture 4.0 supply chain management that has higher efficiency, effectiveness, and security in comparison to conventional blockchains. We design a Multi-Layer Aggregate Verification (MLAV) solution to improve supply chain management with IoT Blockchain for Agriculture 4.0 through the following methods. First, we use a multi-layer IoT blockchain system to reduce Ethereum gas fee. Second, we design an ID-based Aggregate Verification scheme, thereby eliminating the certificate management cost in the traditional Public Key Infrastructure (PKI) and reducing bandwidth and computation time requirements. Third, we implement a three-layer blockchain infrastructure. In Layer 1, IoT devices sense and upload data to the system’s database; in Layer 2, smart contracts execute aggregate ID-based signature verification from IoT devices and upload the transactions to the private blockchain; in Layer 3, a batch converts the layer 2 data and uploads its Merkle root to Ethereum, thereby reducing the required gas fee. 1 Introduction This paper is an extension of a work originally presented in BRAINS 2021 [1] that uses a multi-layer architecture designed to facilitate smallholders in joining an agricultural blockchain infrastructure. We use aggregate verification to solve the efficiency bottleneck of ID-based signature verification. We also lay out the framework for distributed supply chain management for access control with smart contracts to allow the smallholder to gain access to loans. With the ushering in of Agriculture 4.0, in recent years there has been widespread adoption of technologies such as the Internet of Things, big data, artificial intelligence, cloud computing, and re- mote sensing [2]. Agriculture 4.0, also known as digital farming or smart farming, has been brought about by combining telematics and data management with known precision agriculture concepts. These changes have improved the accuracy and practicality of farming operations [3]. However, regarding data management, food safety, and quality monitoring of the agricultural supply chain, Agriculture 4.0 still has significant shortcomings. Particularly in the COVID-19 pandemic, it is essential to prevent cross-contamination and food pathogen out- breaks. The agricultural supply chain should have data transparency, and there should exist a high level of traceability from source to consumer. The World Government Summit in 2018 pointed out that Agriculture 4.0 will need to focus on both the demand side and the value chain (supply) side of the food equation to use tech- nology to meet the real needs of the consumer and to re-engineer the value chain [4]. The tamper-proof property and transparency of blockchain technology allow it to meet these requirements effec- tively. IoT Blockchain is highly suited for ensuring traceability and consistency of information generated by IoT devices. Large companies have already begun to adopt distributed supply chain management systems with blockchain technology. In 2017, Walmart established the Walmart Food Safety Center in Beijing and invested US$25 million to use IBM’s blockchain solutions to build a global food safety system [5] already tracking 1,500 items on the supply chain blockchain in 2021. Proof of Concept (PoC) and blockchain pilot projects have been established in the United * Corresponding Author: Shih-wei Liao, Email: liao@csie.ntu.edu.tw www.astesj.com https://dx.doi.org/10.25046/aj070312 106