A vehicular ad hoc network (VANET) allows for vehicles on roads to form a self-organized network and broadcast messages among them. However, as data are transmitted in an insecure network, it is essential to use an authentication mechanism to protect the privacy of vehicle users. Recently, Ying et al. proposed an authentication protocol for secure vehicular networks and claimed that the protocol could resist various attacks. Unfortunately, we discovered that their protocol suffered from an offline identity guessing attack, location spoofing attack, and replay attack, and consumed a considerable amount of time for authentication. To resolve these shortcomings, we propose an improved protocol. In addition, we provide a formal proof to the proposed protocol to demonstrate that our protocol is indeed secure. Compared with previous methods, the proposed protocol performs better in terms of security and performance.

Public key encryption with keyword search, known as PEKS, is a useful technology in some Storage-as-a-Service clouds. This technology allows the cloud server to search on a keyword, which is received from the data owner/user, over encrypted data without having the ability to decrypt the stored data. PEKS with designated verifier, known as dPEKS, further advances the security of PEKS such that only a designated server can perform the keyword searching. Combining the certificateless technology, which aims to avoid the key escrow problem in ID-based cryptography, produces a certificateless dPEKS scheme that inherits the property of certificatelessness in key management in the dPEKS. This paper presents a provably secure certificateless dPEKS which has fixed an insecure scheme which was proposed earlier. The scheme presented in this paper is proven to be secure under Bilinear Diffie–Hellman problem.

Security issues become more and more significant in RFID development. Recently, Chien proposed an ultralightweight RFID authentication protocol in order to achieve privacy and authenticity with limited computation and transmission resources. However, we find two desynchronization attacks to break the protocol. In order to repair the protocol, two patches that slightly modify the protocol are presented in the paper.