# Securing SCADA Energy Management System under DDs Attacks Using Token Verification Approach
## 1 Introduction
The Energy Management System (EMS) [9] is a service for monitoring, managing, and controlling energy. The growing maturity of IIoT technology has resulted in many new applications; for example, the Building Energy Management System (BEMS) [10] has been applied in resident-centered housing together with the demand response (DR) to balance the supply and demand of power and avoid energy waste [11]. The smart green energy management system covers a wide range of technologies, including SCADA, CEMS, BEMS, PLC, and IIoT technology. At present, the difference between Operational Technology (OT) and Information Technology (IT) [12] represents the major reason why enterprises in the IIoT sector pay little attention to information security. Basically, IIoT uses physical isolation and is separated from the external network, which means enterprises may be attacked by external viruses due to administrative negligence and uncertainty in physical isolation. Previously, OT and IT had separate environments, and each had its own responsibilities. Today, as the growing availability of the internet enables the two systems to gradually connect with each other, the nature and architecture of OT and IT are different and the existing management and implementation method for information security may not be effective in defending against attacks; for example, as ICS must be in constant operation, it is relatively difficult to stop it for a security update and may cost a lot of money. Moreover, it takes ten minutes or more for some ICS systems to restart after powering off and major losses may be incurred during this period. In terms of product life expectancy, while ICS can be used for a long time, ranging from 10 years to 20 years, the design and manufacture of these systems do not consider information security; therefore, updating and replacing hardware and software, as well as installing, updating, and fixing programs in ICS, is very difficult. In addition, the network device that ICS connects with may have insufficient defense capability and fail to detect and process malicious traffic or large common traffic. In the environment of the Internet of Things, due to the interconnection of a large number of devices, it is a common method to prevent unknown malicious attacks through authentication protocols. In the issue of authentication, there are many solutions and considerations. First of all, in the application of sensors, the solution must take into account that the trade-offs between lightweight, low power consumption and security. In addition, how the authentication mechanism prevents potential attacks such as Sybil, replay, password guessing, message forgery, man-in-the-middle, and DoS is also an important feature of the evaluation. In [13], it is mentioned that the authentication scheme needs special consideration of distributed denial of service attacks. In particular application scenarios, location and privacy need to be considered. In practical deployment, the authentication solution must be scalable, and involving the three-layer architecture (perception layer, network layer and application layer) of the Internet of Things, and the ability to add new devices without any further settings or configuration. The authentication methods of the Internet of Things are mainly divided into hardware-based (True Random Number Generator (TRNG), Physical Unclonable Function (PUF) and Trusted Platform Module (TPM)), token-based and procedure (one-way, two -way and three-way) [13]. The authors of [14] proposed an xTSeH (TPM extension scheme) architecture using TPM modules to implement a shadow TPM in the form of kernel modules to ensure integrity. Due to the limitation of hardware capabilities, not all IoT devices can be equipped with TPM chips. Therefore, Trusted Booting Protocol (TBP), Remote Verification Protocol (RVP) and Node Authentication Protocol (NAP) are mainly used to achieve integrity verification and authentication between devices.