## 2 Authentication in the Smart Grid (SG) Network
### Authentication Protocols
Furthermore, if the system is not secure against various security attacks and failures, the adversary can compromise the system resources and can affect the authentication process. This may happen if the adversary is able to drop some information or control message that is needed to complete the authentication process. In this case, even if the authentication is fast and efficient, it will never complete. Since there are billions of entities involved in the SG network, installation and uninstallation of the devices in a secure and authentic manner requires trust among these entities. In other words, the device, as well as the engineer, must be verified by the controller in the SG network when these operations are performed that may require trusted hardware setup. A secure and efficient buffer management may be required at the AGs in the SG network, which are responsible for receiving a large volume of information from the various SMs, and at the memory stack of controlling devices in the SCADA system to prevent buffer overflow-based DoS attacks. Furthermore, the confidentiality is strongly required along with the privacy preservation of the information. In the SG network, we need to hide the identity and other relevant information of the devices, such as SMs and EVs, from the other entities. For example, a compromised AG may breach the privacy of the SM and can harm/mislead the user by tracing its pattern and energy consumption details. Similarly, some personal information, such as consumed units in every time slot, need to be encrypted over the network when providing it to an untrusted entity, such as an AG. Moreover, the performance of the system is important for satisfying the system requirements as well as supporting a huge number of devices. The evaluation metrics comprise of communication and computation overheads generated by the protocol, execution time of the protocol, delay at intermediate entities, and message transmission time. A solution is scalable, if it can support the authentication for a huge number of devices and can be further extended if required, with reasonable execution time and low overheads. Timing accuracy in the SG varies from few microseconds to few seconds depending upon different communication scenarios among various entities. In power communication networks, such as smart grid, reliability, security, and real-time message delivery have higher priorities than providing high throughput. Therefore, latency requirement is much more important in smart grid system [32]. The communication latency needed for the transmission system protection is in the order of a few milliseconds [33] and authentication time varies up to few seconds [1]. Furthermore, the computation complexity of various functions used in the protocol should be as low as possible to be scalable. The security and performance objectives for developing a secure and efficient authentication protocol with secure network environment in the SG network end-to-end at power distribution among various entities, such as users, devices, CC, utility provider, _etc._, are listed as follows:  
Obj-1: Low execution and protocol delay;  
Obj-2: Low computational and storage cost;  
Obj-3: Low communication and computation overhead;  
Obj-4: Resistance to attacks and failures;  
Obj-5: Trust among SG entities;  
Obj-6: Buffer management;  
Obj-7: Confidentiality and privacy.