Security Analysis of Several Chosen Ciphertext Secure Group-oriented Encryption Schemes

In Journal of Systems Engineering and Electronics, Maet al. proposed a broadcast group-oriented encryption secure against chosen cipher text attack scheme, later they proposed several other chosen cipher text secure group-oriented encryption schemes, based on this scheme, they also proposed a group-based proxy re-encryption scheme secure against chosen cipher text attack. However, in this paper we will show that these schemes are not chosen cipher text secure.