Hardening secure search in encrypted database: a KGA-resistance conjunctive searchable encryption scheme from lattice

A lattice‐based searchable encryption scheme with multi‐user authorization for the certificateless cloud computing environment

“…As shown in Figure 5, the time cost of the trapdoor generation algorithms for YXX22 31 and MXX21 33 is higher than that of our scheme. Furthermore, our scheme exhibits a more gradual linear change in the time cost of its trapdoor generation algorithm as the number of keywords increases, compared to the others.…”

“…As indicated in Table 3, Test algorithm of MXX21 33 involves $$$ t $$$ the matrix multiplication operations, while our scheme's Test algorithm requires $$$ 2t $$$ the matrix multiplication operations and matrix inverse operations, resulting in higher Test algorithm time cost compared to MXX21 33 . However, in comparison to the Test algorithm time cost of YXX22, 31 as shown in Figure 6, our scheme exhibits lower time costs. Although the test algorithm in our scheme involves the matrix inverse operation, it should be noted that the inversion matrix is only related to the CS private key.…”

“…From Table 4, we can observe that LLW21 8 and LHS19 32 are vulnerable to quantum computer attacks due to the need for certain pairing and exponentiation operations on group elements. Additionally, YXX22, 31 LHS19, 32 and MXX21 33 cannot completely resist three types of KGA. The comparison reveals that our framework provides resistance against all three known types of keyword guessing attacks while demonstrating superior performance.…”

“…In this part, we compare our scheme with other searchable encryption schemes, including YXX22, 31 LLW21, 8 LHS19, 32 and MXX21 33 . Compared to standard searchable schemes, our scheme incurs additional storage overhead for re‐encrypted ciphertexts, re‐encryption keys, and verification blocks due to the requirement of multi‐user authorization and result integrity verification.…”

“…As shown in Figure 4, due to the significantly higher time cost of matrix inverse operations compared to sampling operations, our scheme's Encrypt algorithm, for $$$ l $$$ keywords, requires $$$ \left(l+1\right) $$$ hash operations, $$$ 3l $$$ the matrix multiplication operations, and SamplePre operations, whose time cost is much lower than MXX21 33 and slightly higher than YXX22 31 . However, our scheme combines ciphertext encryption with search authorization, allowing for multi‐user search authorization.…”