A Novel Model for Lattice-Based Authorized Searchable Encryption with Special Keyword

Abstract

Data stored in the cloud servers, keyword search, and access controls are two important capabilities which should be supported. Public-keyword encryption with keyword search (PEKS) and attribute based encryption (ABE) are corresponding solutions. Meanwhile, as we step into postquantum era, pairing related assumption is fragile. Lattice is an ideal choice for building secure encryption scheme against quantum attack. Based on this, we propose the first mathematical model for lattice-based authorized searchable encryption. Data owners can sort the ciphertext by specific keywords such as time; data users satisfying the access control hand the trapdoor generated with the keyword to the cloud sever; the cloud sever sends back the corresponding ciphertext. The security of our schemes is based on the worst-case hardness on lattices, called learning with errors (LWE) assumption. In addition, our scheme achieves attribute-hiding, which could protect the sensitive information of data user.

A Novel Lattice-Based CP-ABPRE Scheme for Cloud Sharing

“…Zhang et al [16] presented a ciphertext policy attribute-based encryption (ABE) scheme based on learning with errors (LWE), which is widely believed to be secure in quantum computer attacks. Zeng et al [17] presented an authorized searchable encryption with special keyword based on [16].…”

“…In this paper, (1) we constructed a lattice-based CP-ABE scheme by modifying the ABE scheme of Zeng et al [17]. Compared with the ABE schemes of [16,17], our CP-ABE scheme has smaller public parameters.…”

“…In this paper, (1) we constructed a lattice-based CP-ABE scheme by modifying the ABE scheme of Zeng et al [17]. Compared with the ABE schemes of [16,17], our CP-ABE scheme has smaller public parameters. 2We constructed a CP-ABPRE scheme based on the new CP-ABE scheme by using trapdoor sampling from LWE, which is widely believed to be secure in quantum computer attacks.…”

“…There are only two lattice-based ABE schemes that support this operation. Compared with the ABE scheme of [16,17], our scheme not only supports proxy re-encryption but also has smaller public parameters. The comparison results are given in Table 2.…”

“…Therefore, the correctness of the CP-ABPRE-KS scheme can be proved by the correctness of the CP-ABPRE scheme. Based on the security definition of [17,21], we can define the IND-sAS-CKA (chosen keyword attacks) secure at the original ciphertext for the CP-ABPRE-KS scheme by modifying Definition 3 as follows:…”