Secure Data Sharing through Untrusted Clouds with Blockchain-enhanced Key Management

With the rapid development of cloud technology and the huge amount of big data generation, outsourcing data storage to a cloud service provider is an efficient solution. The challenges on the trustworthiness of cloud providers are urgent to be solved due to many security and privacy violation incidents in recent years. Some enhanced data protection methods such as All-Or-Nothing Transformation (AONT) are proposed to provide additional protection on data security. However, the key management and access revocation operations will become a difficult task and the key manager will be vulnerable. In this paper, we propose to use the scalable consortium blockchain system to solve the key management for the AON-based data protection and outsourcing in the multi-clouds scenario. We propose a model that can provide secure data sharing through untrusted clouds with the key management provided by the consortium blockchain system as a service. We also provide practical case studies for using the novel AON data approaches to protect data security and tamper-proofing on key management.