Wireless sensor networks (WSNs) have great potential for numerous domains of application because of their ability to sense and understand unattended environments. However, a WSN is subject to various attacks due to the openness of the public wireless channel. Therefore, a secure authentication mechanism is vital to enable secure communication within WSNs, and many studies on authentication techniques have been presented to build robust WSNs. Recently, Lu et al. analyzed the security defects of the previous ones and proposed an anonymous three-factor authenticated key agreement protocol for WSNs. However, we found that their protocol is vulnerable to some security weaknesses, such as the offline password guessing attack, known session-specific temporary information attack, and no session key backward secrecy. We propose a lightweight security-improved three-factor authentication scheme for WSNs to overcome the previously stated weaknesses. In addition, the improved scheme is proven to be secure under the random oracle model, and a formal verification is conducted by ProVerif to reveal that the proposal achieves the required security features. Moreover, the theoretical analysis indicates that the proposal can resist known attacks. A comparison with related works demonstrates that the proposed scheme is superior due to its reasonable performance and additional security features.

Nowadays, due to the rapid development and wide deployment of handheld mobile devices, the mobile users begin to save their resources, access services, and run applications that are stored, deployed, and implemented in cloud computing which has huge storage space and massive computing capability with their mobile devices. However, the wireless channel is insecure and vulnerable to various attacks that pose a great threat to the transmission of sensitive data. Thus, the security mechanism of how the mobile devices and remote cloud server authenticate each other to create a secure session in mobile cloud computing environment has aroused the interest of researchers. In this paper, we propose an efficient and provably secure anonymous two-factor user authentication protocol for the mobile cloud computing environment. The proposed scheme not only provides mutual authentication between mobile devices and cloud computing but also fulfills the known security evaluation criteria. Moreover, utilization of ECC in our scheme reduces the computing cost for mobile devices that are computation capability limited and battery energy limited. In addition, the formal security proof is given to show that the proposed scheme is secure under random oracle model. Security analysis and performance comparisons indicate that the proposed scheme has reasonable computation cost and communication overhead at the mobile client side as well as the server side and is more efficient and more secure than the related competitive works.

Wireless sensor network has been widely used and plays a vital role in the Internet of Things, smart cities, military, and other fields, and its security has also attracted the attention of many researchers. In view of the security defects in Shin and Kwon’s scheme such as failure to provide three-factor security, lack of anonymity and untraceability, user impersonation attack, desynchronization attack and privileged insider attack, we suggest an improved provably secure three-factor user authentication scheme based on Chebyshev chaotic mapping for wireless sensor network, which employs fuzzy verifier technique to prevent attacker from offline guessing attack on user identity and password when the stolen/lost smartcard is acquired by the attacker. During the authentication phase, a dynamic identity mechanism is used to ensure the anonymity of the user and sensor to prevent desynchronization attack, and the Chebyshev chaotic mapping is introduced to improve security and reduce computation overhead. The rigorous security proof under the random oracle model and the formal verification via ProVerif show that our protocol overcomes the weaknesses in Shin and Kwon’s scheme. In addition, by comparing the performance of our proposed scheme with that of others, we demonstrate that our proposal not only solves the security risks of Shin and Kwon.’s protocol, but also achieves a better tradeoff between security and efficiency, therefore, it is more suitable for user authentication in wireless sensor network environments.

Wearable health monitoring system (WHMS), which helps medical professionals to collect patients’ healthcare data and provides diagnosis via mobile devices, has become increasingly popular thanks to the significant advances in the wireless sensor network. Because health data are privacy-related, they should be protected from illegal access when transmitted over a public wireless channel. Recently, Jiang et al. presented a two-factor authentication protocol on quadratic residues with fuzzy verifier for WHMS. However, we observe that their scheme is vulnerable to known session special temporary information (KSSTI) attack, privileged insider attack, and denial-of-service (DoS) attack. To defeat these weaknesses, we propose an improved two-factor authentication and key agreement scheme for WHMS. Through rigorous formal proofs under the random oracle model and comprehensive informal security analysis, we demonstrate that the improved scheme overcomes the disadvantages of Jiang et al.’s protocol and withstands possible known attacks. In addition, comparisons with several relevant protocols show that the proposed scheme achieves more security features and has suitable efficiency. Thus, our scheme is a reasonable authentication solution for WHMS.

Wireless medical sensor networks (WMSNs) play an important role in collecting healthcare data of the remote patient and transmitting them to the medical professional for proper diagnosis via wireless channel. To protect the patient's healthcare data which is private-related and sensitive, some authentication schemes for healthcare systems using WMSN have been proposed to ensure the secure communication between the medical sensors and the medical professional. Since cryptanalyzing the security defects of authenticated protocols is crucial to put forward solutions and propose truly robust protocols, we scrutinize two state-of-the-art authentication protocols using WMSN for healthcare systems. Firstly, we examine Ali et al.’s enhanced three-factor based authentication protocol and show that although it provides a formal proof and a security verification, it still fails to resist offline dictionary guessing attack, desynchronization attack, and privileged insider attack and contains a serious flaw in the password change phase. Secondly, we investigate Shuai et al.’s lightweight and three-factor based authentication protocol and point out that it cannot achieve high security level as they claimed; it is actually subject to offline dictionary guessing attack and privileged insider attack, and it also has a design flaw in the password change phase. In addition, we suggest several countermeasures to thwart these security weaknesses in these two schemes for WMSN and the similar kinds.