Updatable and Dynamic Searchable Symmetric Encryption Scheme with Forward and Backward Privacy

Dynamic searchable symmetric encryption (DSSE) enables search and modification on encrypted data. While considerable efforts have been dedicated to achieving forward and backward privacy in DSSE, the potential adverse consequences of key corruption or exposure have been overlooked. In this paper, we introduce the updatability into DSSE to resist the key exposure attacks, propose a new concept named updatable and dynamic searchable symmetric encryption (U &D-SSE), and establish \(\mathcal {L}\) -adaptive security model tailored to the update environment. Then we construct a U &D-SSE scheme with token inference, where a ciphertext can be updated by a token and a key can be inferred in bi-direction. Furthermore, a U &D-SSE scheme with token-free inference is proposed to achieve no-directional key update through indistinguishable obfuscation. Finally, both schemes are proven to be secure in the \(\mathcal {L}\) -adaptive security model, and ensuring the preservation of forward and backward privacy.