Cryptology ePrint Archive: Report 2019/1123

FSPVDsse: A Forward Secure Publicly Verifiable Dynamic SSE scheme

Laltu Sardar and Sushmita Ruj

Abstract: A symmetric searchable encryption (SSE) scheme allows a client (data owner) to search on encrypted data outsourced to an untrusted cloud server. The search may either be a single keyword search or a complex query search like conjunctive or Boolean keyword search. Information leakage is quite high for dynamic SSE, where data might be updated. It has been proven that to avoid this information leakage an SSE scheme with dynamic data must be forward private. A dynamic SSE scheme is said to be forward private, if adding a keyword-document pair does not reveal any information about the previous search result with that keyword.

In SSE setting, the data owner has very low computation and storage power. In this setting, though some schemes achieve forward privacy with honest-but-curious cloud, it becomes difficult to achieve forward privacy when the server is malicious, meaning that it can alter the data. Verifiable dynamic SSE requires the server to give a proof of the result of the search query. The data owner can verify this proof efficiently. In this paper, we have proposed a generic publicly verifiable dynamic SSE (DSSE) scheme that makes any forward private DSSE scheme verifiable without losing forward privacy. The proposed scheme does not require any extra storage at owner-side and requires minimal computational cost as well for the owner. Moreover, we have compared our scheme with the existing results and show that our scheme is practical.

Category / Keywords: applications / Searchable encryption, Forward privacy, Verifiability, BLS signature, Cloud computing

Original Publication (with minor differences): The 13th International Conference on Provable and Practical Security (ProvSec 2019)

Date: received 30 Sep 2019, last revised 24 Dec 2019

Contact author: laltuisical at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20191224:144412 (All versions of this report)

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