Wang, Wu, Li, Du, and Luo proposed a public key searchable encryption scheme (Electric Power Systems Research 2022 (SJR Q1 Journal)). They claimed that no keyword information is revealed by either a ciphertext or a trapdoor. In this short note, we demonstrate that keyword information is indeed revealed from both a ciphertext and a trapdoor.
Emura et al. (Thu,) studied this question.