In cloud and edge computing environments, outsourcing is a common way for resource-constrained customers to complete complex tasks. With the rapid technological advancements in Internet of Things (IoT), edge computing, cloud computing, big data, machine learning, social networking, and next-generation communication systems, outsourcing services have received unprecedented attention. As typical outsourcing services, outsourcing computations and outsourcing storage have a wide range of applications including federated learning, data sharing, proof of ownership, scientific problem solving, data mining, big data analysis, etc., which could, in turn, further boost the development of the above emerging technologies.

The wide-scale adoption of outsourcing services should further take several challenges into account. For one thing, the state-of-the-art security technologies assume the existence of a trustworthy and uncompromised third party, which undermines decentralization and transparency. For another, the sensitive payment issue of outsourcing services has seldom been considered. Traditionally, the default payment mechanism is enabled by a fully trusted bank, which fails to realize fairness and robustness. Finally, the forensics of malicious behaviours in outsourcing services remains to be addressed. Therefore, it is essential for research communities to solve these problems associated with outsourcing services and to develop decentralized and accountable security technologies. Till now, blockchain is regarded as a promising technique that is characterized by decentralization and tamper resistance. However, it is particularly challenging to use blockchain technologies in outsourcing services in that the blockchain technology is still in its infancy and limited research efforts have been done on blockchain-enabled outsourcing services in cloud and edge computing.

This Special Issue aims to bring together researchers and practitioners to discuss advanced academic and industrial research results related to blockchain technologies for decentralization and forensics of outsourcing services in cloud and edge computing. Original research and review articles are welcome.

Potential topics include but are not limited to the following:

• Blockchain-enabled data sharing and trusted storage in cloud and edge computing
• Blockchain for decentralization and forensics of provable data possession
• Trustworthy searchable encryption in cloud and edge computing
• Decentralization and forensics for trusted federated learning
• Blockchain-based identity management in cloud and edge computing
• Decentralized and transparent attribute-based encryption
• Decentralized and transparent outsourcing computation in cloud and edge computing
• Decentralization and forensics for data mining and big data analysis
• Smart contract for smart grid and vehicular communication
• Blockchain for fair payment mechanisms of outsourcing services
• Blockchain-based incentive mechanisms for outsourcing services
• Blockchain-based trust and reputation management in cloud and edge computing