Cryptanalysis of ``FS-PEKS: Lattice-based Forward Secure Public-key Encryption with Keyword Search for Cloud-assisted Industrial Internet of Things\u27\u27

In this note, we review lattice-based public-key encryption with the keyword search against inside keyword guess attacks (IKGAs) proposed by Zhang \textit{et al}. in IEEE Transactions on Dependable and Secure Computing in 2021. We demonstrate that this scheme is insecure for IKGAs, although Zhang \textit{et al.} demonstrated a secure proof