Cryptanalysis of the certificateless encryption schemes strongly secure in the standard model

摘要

Certificateless cryptography solves the key escrow problem that is inherent in the ID-based in the identity-based cryptography. In PKC 2008, Dent et al. proposed a certificateless encryption schemes strongly secure in the standard model. They claimed that their CLE encryption scheme is provably strongly secure against a strong type I adversary and type II adversary. In this paper, we show that their certificateless encryption scheme is completely insecure and the claim of provable security is seriously incorrect by a type I adversary who can replace users' public keys and access to the encrypting oracle under the replaced public keys.