Blockchain is considered a new generation of information technology for supporting distributed systems with fault tolerance. With immutability and decentralization, blockchain has been successfully used in designing many cryptocurrencies to maintain transactions among distributed users. Moreover, blockchain can develop emerging decentralized systems in many fields, ranging from edge/cloud computing or the Internet of Things, to supply chains and sustainable manufacturing, among many others.

However, the advancement of emerging blockchain-empowered applications is still in the early stages due to a lack of standardization and weak interoperability of blockchain technologies. More importantly, critical issues, such as security, privacy, and scalability, significantly hinder the development and deployment of blockchain-empowered systems in real-world scenarios. Furthermore, existing security solutions may compromise the transparency of blockchain and the regulation of on-chain transaction details. Therefore, there is an urgent need for breakthroughs in theories and technologies for blockchain and blockchain-empowered systems.

This Special Issue aims to solicit high-quality research and review articles focusing on the latest advances in securing the blockchain and its applications, including advanced theories, methods, technologies, and emerging applications. Although existing research results have shown significant progress towards securing blockchain-empowered applications, numerous research challenges are yet to be addressed. This Special Issue hopes to allow researchers to present the latest developments and discuss the future directions of this field.

Potential topics include but are not limited to the following:

• New theories, methodologies, and architectures for securing blockchain and smart contracts
• Robustness, reliability, performance, and fairness issues in blockchain-empowered systems
• Security and privacy issues in blockchain-empowered applications
• Provable secure cryptographic protocols for blockchain-empowered systems
• Cross-chain, side chain, and sharding techniques for scalability and interoperability in blockchain
• Blockchain-based frameworks for smart energy, smart grids, smart business, and smart cities
• Blockchain-based frameworks for securing intelligent transportation systems
• Blockchain-enabled techniques for securing big data systems, social networks, and sensor networks
• Blockchain-enabled techniques for authentication, access control, tracing, and supervision
• Blockchain-enabled techniques for securing crowdsourcing and crowdsensing
• Blockchain-based lightweight methods and protocols for the Internet of Things
• Blockchain-based secure protocols for cloud/edge/fog computing
• Artificial intelligence, machine learning, or federated learning techniques for blockchain security
• Proof-of-concept and analytics of blockchain-empowered systems