To solve privacy leakage and other security problems in Radio-Frequency Identification (RFID) tag authentication and tag ownership transfer, and to simplify the design of tag ownership transfer protocol, an RFID authentication protocol enabling tag ownership transfer was proposed for those tags that support Elliptic Curve Cryptography (ECC). The structure of the protocol is similar to the structure of the Diffie-Hellman logarithm, and tag privacy of the protocol is based on complexity to solve the computational Diffie-Hellman problem. Analysis of tag privacy and other security properties of the protocol were given, and comparisons between recent ECC-based authentication protocols and the proposed protocol were also given. The results show that the proposed protocol achieves best performance, under a comprehensive evaluation of supporting tag ownership transfer, tag computation cost, communication cost and tag privacy protection. In addition, a simplified version that realizes tag authentication to reader and is suitable for secure environments was also given.

Due to user revocability, the new data manager needs to verify the integrity of the former data manager's management data stored in the cloud server, which is obviously inevitable in reality. In order to solve this issue, an efficient privacy-preserving public auditing scheme for cloud storage scheme was proposed. Firstly, in the proposed scheme based on unidirectional proxy re-signature, the proxy re-signature key was generated by the current data manager's private key and the former public key, which did not leak any information, to realize transferring of ownership data caused by the users revocability securely. Secondly, it was proved that the proposed scheme could protect any malicious cloud server from generating the forged response proof which could pass the verification to cheat the Third Party Auditor (TPA). Moreover, the random masking technique was employed to prevent the curious TPA from revealing the primitive data blocks. Compared with the Padna scheme, even though the proposed scheme adds the new functions but its communication overhead in the process of auditing and computational cost are also lower than Panda's.