How the control over smart meters is lost in the Yan et al. lightweight AKA scheme for smart grids

The emerging Internet of Things (IoT) offers major improvements to many applications such as Smart Grid. The discovery of security threats are becoming a challenge to fulfill the purpose of the IoT ecosystem. Designing lightweight Authentication and Key Agreement (AKA) protocols are critical to establish mutual authentication while reducing overloads on particular constrained devices including Smart Meters. The Yan et al. lightweight AKA scheme was proposed to provide mutual authentication along with multicast mechanism and other features for Smart Grids which facilitates power management while maintaining it's security and privacy. However, in this paper we show that the Yan et al. lightweight AKA scheme is vulnerable to replay attack in the multicast key generation phase in which the control over Smart Meters could be lost. Specifically, in this scheme, the attacker is able to interrupt the multicast messages without revealing the interruption to the Building Area Network (BAN) gateway. So, the desired Smart Meters do not receive any emergency multicast messages during power outages for a while. So there is a disturbance in the Smart Grid that could result in a Denial of Service (DoS) attack.