Security Flaws of a Password Authentication Scheme for Hierarchical WSNs

With the growing popularity of sensor-based monitoring devices, sensor networks are becoming an essential part of wireless heterogeneous networks and numerous researches have been widely studied in recent years. Recently, Das et al. proposed a dynamic password-based user authentication scheme with dynamic node addition for hierarchical wireless sensor networks (WSNs). They claimed that their scheme achieves better security as compared to those for other existing password-based user authentication approaches. However, we observe that Das et al.'s scheme is vulnerable to smart card breach attack, privileged-insider attack, and many logged-in users' attack and is not easily reparable.