A Note on “AESM2 Attribute-Based Encrypted Search for Multi-Owner and Multi-User Distributed Systems”

We show that the attribute-based encrypted search protocol [IEEE TPDS, 2023, 34(1), 92–107] is insecure against unauthorized user querying attack, because an adversary can convert a valid query from any authorized user into a new legitimate query, while the server cannot detect the fraud.