Cryptanalysis of “Certificateless remote data integrity checking using lattices in cloud storage”

C. Sasikala et al.'s proposed a certificateless RDIC protocol to audit the outsourced data without the requirement of PKI infrastructure and against quantum computer attacks. They argue the RDIC is correct and possesses desired security properties. However, through cryptoanalysis technique we find that their scheme is neither correct nor secure against two common attacks, that is, signature forgery attack from the malicious cloud service provider (CSP) and public key replacement attack from the curious private key generator (PKG) and other malicious users. Furthermore, we remark that their RDIC is not a rigorous certificateless protocol.