## 1 Introduction
Data integrity refers to maintaining accuracy and consistency of the data in the database or when transmitted over the network, while secure integrated communication allows a reliable real-time information exchange within the system. Data integrity can be maintained by using either hash functions, such as SHA1, SHA256, _etc._, in which variable length input is converted into a fixed length hash code, or by the message authentication code (MAC) functions, such as cipher-based message authentication code (CMAC), hash-based message authentication code (HMAC), one-time MAC, _etc._, where variable length input with a secret key is mapped to a fixed length MAC code. MAC functions provide data integrity as well as authenticity of the message. Figure 1: Overview of smart grid (SG) network architecture. Various communication technologies have been proposed to support integration of SG entities. A comparison chart among various wireless technologies, such as microwave, worldwide interoperability for microwave access (WiMAX), mesh, long term evolution (LTE), 3G cellular, wireless local area network (WLAN), and Zigbee is presented in [14]. Wireless technologies are proposed for backhaul transport in SCADA (Microwave, WiMAX, and LTE) and advanced metering infrastructure (AMI) (Microwave, WiMAX, LTE, mesh, and 3G cellular). Microwave can also be used for backbone transport in SCADA and AMI. Further, demand response can be implemented using microwave, WiMAX, LTE, and mesh, while the distribution automation can be managed by microwave and mesh technologies. WLAN and Zigbee can be used to manage home area network (HAN), smart meter, and home automation. Power line communication (PLC) is also an adopted communication technology in smart meters. In some applications, such as automated meter reading (AMR), street light control, and EV charging, narrowband PLC has captured lot of attention due to its longer range up to several kilometers. On the other hand, broadband PLC has proposed to use in the last mile technology of various applications, like Internet access and home networking and control [15]. The obvious advantage using PLC is the widespread availability of electrical infrastructure and a full control over the physical medium without depending on third party providers, such as telecommunication companies or cellular operators [16]. Although PLC connection has several advantages over the wireless connection, the quality of the connection still depends on the domestic electrical system. Improper wiring and circuit breakers in between the connected cables can negatively affect the performance, and can cause connection interruptions. Many researchers proposed their schemes for the SG and V2G networks in consideration with vehicular ad-hoc network (VANET) and radio frequency identifier (RFID) technology. However, the communication techniques used in VANET and RFID are not directly applicable to the V2G as the entities of these networks behave differently, which are summarized in Tables 1 and 2. The primary concerns of VANET are vehicle safety and optimization of route and traffic flow. On the other hand, the V2G system focuses on battery charge state of electric vehicles (EVs) and management of the availability of parking slots. In the V2G, EVs use charging stations (CSs) according to their ranking and rates of charging, while in the VANET, the vehicles focus on their consumption and emissions [17]. Many researchers proposed RFID-based authentication schemes for the SG network, such as an untraceable server-independent scheme by [PERSON] and [PERSON] [18], to prevent tracing attacks, a mobile RFID-based scheme by [PERSON] _et al._[19], for the SG network, and ADDRESS Box scheme by [PERSON] _et al._[20], to manage the home load. In the RFID-based systems, coexistence proof mainly presents the simultaneous scanning of multiple tags at the same time and place by a reader [21,22]. However, this approach cannot be directly applied in the V2G as it requires a central proof initiator entity.