Blockchain-Based Anti-Key-Leakage Key Aggregation Searchable Encryption for IoT

The Internet of Things (IoT) makes our life more intelligent. Its combination with the cloud server can solve big data processing problems to meet users' needs and bring us great convenience. However, there are two challenges we need to face: data sharing and key leakage. To solve the above challenges, attribute-based encryption (ABE) is used to achieve data sharing combined with searchable encryption (SE). Most of the existing attribute-based searchable encryption (SE) schemes are inefficient and not suitable for IoT devices because of the large amount of attributes and keys. The key-leakage problem is serious in practice which very little literature focused on it. In order to address both problems, in this article, we propose a key aggregation searchable encryption (KASE) scheme based on the blockchain with auxiliary input (AI), which is capable of achieving secure data sharing on the encrypted data. Our scheme is presented through a novel chosen plaintext attack (CPA) secure scheme. We prove our scheme is chosen ciphertext attack (CCA) secure against key leakage under the decisional Diffie-Hellman assumption and Goldreich-Leivin theorem. Moreover, we adopt the proposed scheme to establish a data-sharing system based on blockchain, which improves search efficiency and connects the global ecology. In addition, extensive performance evaluations are conducted, and the results indicate our scheme is really efficient in cloud-computing-enhanced IoT.