Towards Public Verifiable and Forward-Privacy Encrypted Search by Using Blockchain

【Author】 Guo, Yu; Zhang, Chen; Wang, Cong; Jia, Xiaohua

【Source】IEEE TRANSACTIONS ON DEPENDABLE AND SECURE COMPUTING

【影响因子】6.791

【Abstract】Dynamic Searchable Symmetric Encryption (DSSE) is a practical cryptographic primitive that assists servers to provide search and update functionalities in the ciphertext domain. Recent work on DSSE schemes has focused on the direction of forward-privacy, requiring that newly added files cannot be linked to previously query results. However, due to the complexity of forward-privacy updates, existing schemes can only address an honest-but-curious server. It is difficult to verify updated results while preserving forward-privacy. In this paper, we explore how blockchain techniques can help us achieve a verifiable and forward-privacy DSSE scheme. Our scheme resorts to the emerging smart contract as a trusted platform to store digests for public result verification, and carefully crafts dynamic query protocols to enable encrypted search with forward-privacy. In our design, indexes are collocated with encrypted files and stored at storage-servers, which makes the blockchain light-weighted and search operations more efficient. Moreover, we propose a hybrid index design to support efficient files deletion. By using our blockchain-assisted primitive, the property collision between dynamic result verification and forward-privacy can be solved. We formally analyze the security strengths and provide the prototype implementation on Ethereum. Experiment results demonstrate the feasibility and usability of our blockchain-assisted DSSE scheme.

【Keywords】Blockchains; Indexes; Servers; Smart contracts; Privacy; Encryption; Prototypes; Blockchain; dynamic searchable symmetric encryption; forward privacy; verifiable searchable encryption

【发表时间】2023 MAY-JUN

【收录时间】2023-07-05

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