SearchBC: A Blockchain-Based PEKS Framework for IoT Services

Internet of Things (IoT) makes great development and gains popularity with a mature combination with cloud computing. Plaintext data can be encrypted when data owners try to secure the confidentiality, while the encrypted data retrieval can be achieved by a cryptographic primitive named searchable encryption. Public-key encryption with keyword search (PEKS) is built on the asymmetric setting, however, the honest-but-curious assumption in PEKS creates challenges on the search reliability when malicious behaviors happen. It is nontrivial to enable the reliable search while preserving keyword privacy, as users who have paid need to receive either correct-and-wanted results or compensations. In this work, we apply blockchain to resolve this problem and design SearchBC, a blockchain-based PEKS framework supporting private, reliable, and fair encrypted search over the asymmetric setting. SearchBC is built on top of the blockchain and a keyword server to allow fairness in transactions and keyword preprocessing. We present a SearchBC instantiation and formally prove its security under the newly defined security model. SearchBC guarantees that search operations are fair and reliable and that the used keyword keeps privacy. The implementation results show that SearchBC provides a feasible means with reasonable communication and computation costs.

Automated summary

The integration of Internet of Things (IoT) with cloud computing has led to significant developments in encrypted data retrieval, particularly through the use of searchable encryption technology such as Public-key encryption with keyword search (PEKS). This work introduces SearchBC, a blockchain-based PEKS framework designed to ensure private, reliable, and fair encrypted search over the asymmetric setting. SearchBC guarantees fair and reliable search operations while maintaining keyword privacy, offering a feasible solution with reasonable communication and computation costs.